Thanks for the suggestions! I posted an update with some changes I made after playing a bit more. I tested some of the cards suggested as well to varying success.

Carnival / Carnage just feels out of place in the deck if I can't potentially use the second option. The combo of 1 to creature/planeswalker and 1 to player could combo sometimes for Chandra's Spitfire, but in most cases a Shock does the same or better. With burning the player I want as much damage as possible to kill them quickly, and 1 damage generally won't take out a planeswalker unless the opponent is being greedy. I'm actually tempted to remove Chandra's Outrage for a spell with more singular damage. In the same scenario the combo of hitting creature+player can combo for Chandra's Spitfire, but I'm finding I am losing more to creatures with toughness 5+ that I can't get around since all my burn spells cap at 4 damage.

Collision / Colossus would be a decent sidedeck card if I note they are going heavy on flyers since it does 6 damage. Otherwise I'm generally better off with my other burn spells since they are more versatile and allow me to target more options.

Chandra, Flame's Fury isn't a bad option, but the 6 CMC is restrictive on this deck. Generally I'll cap at 4 mana, so I would struggle to play this card without more mana ramp elsewhere such as Runaway Steam-Kin. At that point the deck focus is shifting away from power 1 creatures to just burn, so I feel this would execute better in a more general burn based deck than power 1 creature aggression. Chandra, Acolyte of Flame feels like it would fit the deck better with lower cmc, creating 1 power creatures, and can bring back my spells since most are 3 cmc or less.

Electrostatic Field Actually got me a bit excited. The extra damage per spell would happen somewhat often as long as I have cards to play, but as the game goes on I'm top drawing more and run out of steam for it. I also thought it would trigger Cavalcade of Calamity, so if I ran out of spells I could attack and still trigger that for 1 damage. It's a defender though, so that's not an option sadly. Basically it was good early game and if I have Torbran, Thane of Red Fell that would get crazy real fast. Generally though later on I won't have spells to keep triggering it, and I would be better off with a power 1 creature to at least nibble or trigger Cavalcade of Calamity.

Electrodominance is tempting, but I feel it falls a bit short since the average CMC in the deck is so low. On average I would cast a 2cmc creature or spell with it, so in that case it's 4 mana to do 2 damage and play that 2cmc card. Not great compared to a shock which does it for 1 mana. If I get to 3 mana it starts to become okay, since that would do 3 damage and drop a 3 cmc creature or another burn spell for 5 mana total. That's pretty much were it caps though, as I only go up to 4 CMC and only have a few at that. For a 4 cmc spell it would cost 6 mana, and that would do 4 damage on top of dropping a 4 cmc creature/spell. That sounds pretty good, but not often in this deck since most are 1-2 cmc with a few 3. This seems like it would go much better in a pure red deck or blue/red. Maybe with something like Irencrag Feat and other high cmc creatures/spells.

For Anax, Hardened in the Forge the only real part that matches the deck theme is the on death ability for red creatures. The idea I had was if he is on the field and I have other 1/1, 1/2, etc I could be even more careless with the creatures. As they would trigger Cavalcade of Calamity, and when dying create a 1/1 satyr token which I could use the next turn for another trigger of Cavalcade of Calamity. The deck slots are kinda full so I'm having a hard time finding something to test it with, other than maybe removing Burning Prophet. I could see this working in a more general burn based deck too, since if we factor in a possible Torbran, Thane of Red Fell, those satyrs are doing 3 damage each.

For Torbran, Thane of Red Fell, I have another deck with legendary creatures in a similar fashion and usually land on 3. The reason are I'd rather draw him in most games and have an extra than not at all, because as mid game comes he can help push the final nail in the coffin or give me some extra teeth if I'm running low on creatures. Additionally he is a high priority target, so if the enemy deck has any type of removal he is likely going to get removed within a turn or two. In that case, I would rather be more likely to draw another to get on the field. In my play time so far as well, I still have a decent amount of games where I don't even draw him at 3x in the deck. Although that's more just the shuffle because I've had all 3 show up in my starting hand sometimes too and force a mulligan from me.

Storm's Wrath might be a good replacement for Chandra's Outrage. Same cost that is a good early game board wipe and could take out a lot of the Uncommon Planeswalkers or lower power Mythics that hit the battlefield. Same cost, dealing more power.

I replaced one of Torbran, Thane of Red Fell for Chandra, Flame's Fury mostly as another way to help with burn if a control deck is causing a lot to miss their mark and it gets to mid-game. If you are worried about the the CMC, then Chandra, Novice Pyromancer might be another possible choice. Could justify putting the Pyroclastic Elementals back in, too.

I ordered what I was missing and planning on playtesting it this weekend.

Torbran, Thane of Red Fell is just too good not to be a four-of. It triples the damage from creatures and cavalcade. It's a high-priority target, so it'll get removed often, so you want four. You want to be drawing it as often as possible. Chandra's Pyrohelix seems like a good one here, as well. Chandra, Acolyte of Flame is a great one too.

You'll also need more than 20 lands. I don't care how low your curve is, 22 is a minimum. Maybe 23, with Torbran and how often you want to be double-spelling. Castle Embereth also needs to be a four-of. Activate it after the Cavalcade activations for extra damage.

Re salttotart, Storm's Wrath is a strong card, but generally I don't have a problem with a lot of smaller creatures due to other cards in the deck. It would also kill all my creatures since I have nothing over 4 toughness, and without card advantage I'm likely to have a hard time ramping back up.

Even though my creatures have 1 power, most have 2 or 3 toughness and can trade with other weenies. If Torbran, Thane of Red Fell is there, the weenies can trade with higher toughness creatures easily too. Shock and/or Slaying Fire generally deal with other creatures. Otherwise having full "control" over the board doesn't affect the deck too much. As most of the time people try to out trade me on life with higher power creatures which leaves them open, or I have other ways to hit them directly such as Cavalcade of Calamity, flying on Chandra's Spitfire, the non combat damage on Scorch Spitter, the activated ability for Tin Street Dodger, and just general burn spells.

Chandra, Novice Pyromancer looks nice to tip it towards a higher base cmc again, but I feel it is partly wasted without a true elemental deck. This makes me want to spin off another elemental burn deck though since I would no longer be limited by the low CMC and power 1 creatures.

I'd be interested to hear your results of testing as well. Since I only have a limited pool of people to play with at a table, so most of my games for the deck are on Arena.

re Sorin_Markov_1947 Chandra, Acolyte of Flame is likely on my list next to craft in arena to get some playtime with. The 1/1 elementals synergize so well with both Cavalcade of Calamity and Torbran, Thane of Red Fell, and the -2 would let me replay Shock, Slaying Fire, and spectacle cost on Light Up the Stage. I would also be tempted to add Chandra's Triumph since I would have an actual planeswalker to combo off sometimes.

Chandra's Pyrohelix might actually go back in the deck in favor of Chandra's Outrage. The are a few reasons. Firstly if I add Chandra, Acolyte of Flame, this spell is another option for the -2 to replay (which would make every noncreature in the deck except Cavalcade of Calamity replay options). Secondly if Torbran, Thane of Red Fell is on the field it will spike the damage a lot. From 2 damage to between 4-6 if that triggers how I think it will (2+2 for single target, 1+2 and 1+2 for multiple targets). Third it can be split between creature/player similar to Chandra's Outrage to direct damage where I need it, and combo for Chandra's Spitfire and Spectacle on Light Up the Stage.

Castle Embereth is one of those where if I had everything I would put them in for sure now. Pretty much no downside since the entire deck is mountains, but being rare takes up those wildcards in Arena that could be used on more impactful cards. On that note I am tempted to put in some Dwarven Mine for the 1/1, but the deck having a low land count makes me doubtful it will come into play untapped.

Torbran, Thane of Red Fell I'm torn on actually putting in 4x or keeping 3x since he really ramps up the damage when on the field. In games I am more often to see him but still have a few without him showing up. On the flip side I do have some games with 2 or all 3 of him already in hand with no other supporting cards to play, although that might just be luck of the shuffle more than amount of copies in the deck. This slides into the conversation about mana too so I'll talk about that next.

For the total amount of lands the deck has 27 cards that are cmc 1-2 (lumping Light Up the Stage here since I expect to pay spectacle cost 99% of the time). If I remove Chandra's Outrage for Chandra's Pyrohelix, the only 4 cost is Torbran, Thane of Red Fell and brings the total in cmc 1-2 to 30. When playing if I have 2-3 land in starting hand (which is generally the case with current land base), I'm usually set for the entire match. Most of the deck can limp on 2 mana as well while still being a threat until I draw into a land or Light Up the Stage to dig for one. Burning Prophet scry can help in a pinch too. If the deck hasn't already put a large dent in the opponent by turn 5, a few extra lands for more mana isn't going to help much. On the other hand, a single creature to trigger Cavalcade of Calamity or a burn spell to possibly combo with Torbran, Thane of Red Fell or Chandra's Spitfire can save me.

The reason I say you need more than 20 lands is so that you can cast multiple spells in a turn. Also, 2.33 land in your starting hand is an average, so you'll get it 50% of the time. You don't want to be doing okay on lands 50% of the time, because that means 50% of the time you're screwed.

re Sorin_Markov_1947 I have been thinking over the land situation with your feedback. I think I've been spoiled with Arena BO1's since there are mechanisms in place to try and give your starting hand land based on the deck average cmc. I've only played it a few times on paper and those games had no mana problems, but it is a small testing pool. I ran through a bunch of other starting hands outside of arena and I'm getting 1-2 lands in my starting hand more often, while getting stuck at 2 lands more often as well.

Additionally I missed a key part of the -2 for Chandra, Acolyte of Flame since I have not added her yet. Specifically it allows you to cast the spells from graveyard but you still need to spend the mana. I was originally seeing it as a free cast before, so in this case I would seem to want more land to make sure I can cast those on top of anything else I might cast for turn from hand.

With this information I'm a little torn on what to pull back out to throw in 2 or so more mountains.

I could pull out some Tin Street Dodger, but being a 1 cmc creature with haste means I can combo off with stuff like Cavalcade of Calamity to drop them all in a turn and do damage. The activated ability also helps guarantee I can trigger Cavalcade of Calamity and/or spectacle costs even if they have untapped creatures (not many people appear to main deck defenders). If I'm adding more mana though and increasing chances of floods I'd rather have higher cmc creatures/spells to spend, but there are also good chances I'll be spending the single red mana each turn making him unblockable too (multiple times if I have multiple on the field)

Looking at Burning Prophet as an option to remove as well. It is not as integral as the rest of the creatures for combos, but the scry from casting spells has helped me in a lot of games. Being able to move excess land or lower cost spells away late game helps make sure I draw stronger cards while managing mana flood. Early game it can help in a mana drought too by moving away higher costing spells, but you could point to the fact I wouldn't have those problems with a bit more land. So this might be the one that I remove to make room for more land and Chandra, Acolyte of Flame. I'll still need to find some more slots to open up to fill in copies of Chandra, Acolyte of Flame, but at least this is a start.

I've also considered dropping 1 Scorch Spitter and/or 1 Tibalt's Rager to make room for these changes on top of removing Burning Prophet. The spitter I considered since later on it doesn't do as much by itself. It's just real tempting to keep them in since they fit into most of the deck combos (Chandra's Spitfire, Cavalcade of Calamity, Torbran, Thane of Red Fell). The rager on the flip side provides me with a mana dump on his ability. So later on when I am low on cards or have an abundance of mana I can buff him.

I also obviously would not want to trim out Torbran, Thane of Red Fell so he is off limits. This leaves me with Chandra's Spitfire as the only other creature, but don't want to trim this out either since it is a high priority target from enemies and will win games.

Looking at spells I need Light Up the Stage for card advantage since I'll run out quick, so that's not really an option. Cavalcade of Calamity is an engine, so this also can't get trimmed. Chandra's Outrage is getting replaced with Chandra's Pyrohelix. Slaying Fire is an option, but it's my only real "larger creature" removal while also being versatile to burn a problematic planeswalker or the player directly. Which leaves me with Shock which is a good staple, but maybe I only need 3 since I'll be putting in Chandra's Pyrohelix too? Things for me to think about.

I think 3 burn spells is a bit much, especially with the way the meta is trending. So, yeah, probably cut Slaying Fire. It's a below-average burn spell anyway. Other than that, Burning Prophet is probably the weakest card here, followed by Tibalt's Rager.

So I've made some changes but I have "two" different versions with minor changes right now that I'm playing with to see if I prefer one over the other.

Firstly I removed all 3 Burning Prophet for 3 Chandra, Acolyte of Flame. I then replaced all 3 Chandra's Outrage with 3 Chandra's Pyrohelix. I replaced 4 Mountain with Castle Embereth, even though I only have 1 on paper I had 3 in Arena already. I then wanted to mess with lands a bit, and with Chandra's Pyrohelix being similar to Shock but 1 more cmc I removed 1 Shock for another land. This leaves me with 3 each of Shock and Chandra's Pyrohelix while retaining 3 Slaying Fire for when I need 4+ damage on a single target and all can be replayed from Chandra, Acolyte of Flame. So far it has run well, but only adding 1 land compared to before still keeps it a bit lean at 21.

Another iteration I'm looking at is to make the similar changes to above with the exception that I kept the Shock for 4x. I removed all 3 Slaying Fire to add another Torbran, Thane of Red Fell for 4x total and 2 mountains. This would leave me with just Shock and Chandra's Pyrohelix for burn spells, but if I am more likely to have Torbran, Thane of Red Fell then those burns spells jump up in damage as well to offset the fact I no longer have a higher damage burn spell. This brings the lands to 22 as well, decreasing the change of mana droughts to make sure I can play my cmc 3/4 creatures while emptying my hand of smaller creatures and burn spells towards mid game (hopefully with some Light Up the Stage for card advantage or Chandra, Acolyte of Flame to replay spells/make 1/1s)