Vesperlark is funny with Thunderkin and makes it very hard to permanently kill anything

Zendikar's Roil is kind of meme, but if you get it down with Risen Reef shit gets out of hand fast.

T1/T2? This looks like a very suboptimal version of UR Murktide. I either recommend actually moving in a more counter burn direction with Snappy, or just change the deck to be more like Murktide. You're missing DRC, bauble, heat, and Iteration which are all very strong cards.

Hateful Eidolon?

I mean extraction is actually really nice against tron if you can manage to get one of the lands in the yard before that land type is on the battlefield

And instead of Fragmentize I recommend Wear / Tear. Torpor Orb may also be better than Hushbringer unless there's a ton of creature dying stuff going on in your meta.

Esper Sentinel is a great one drop, I recommend you run all 4. And it becomes even better with Tempered Steel.

I'd cut Shrapnel Blast, 4 Galvanic is already good.

I do love Nettlecyst, but I'm unsure how good it is here because the germ token actually isn't an artifact creature, so it isn't buffed by Tempered Steel.

Urza's Saga is super strong, I highly recommend the Saga + Shadowspear + Soul-Guide Lantern + Pithing Needle etc package.

Portable Hole may be better than Prismatic Ending here. Dispatch is a great sideboard option for stuff like murktide or decks that like to abuse the yard.

umezawa is so obviously pushed for edh but whatever, still gonna try to make it work in modern lmao

I feel like you really want a singleton enchantment sac outlet that you can get with Idyllic and Commune.

Did a quick search on scryfall and found a lot of good repeatable sac outlets that aren't modern legal... then found Goblin Bombardment which I forgot they reprinted. It isn't GW however, which is unfortunate. I also found Greater Good... which will probably end up with you milling out and also discarding more cards than you draw.

Ok after a more thorough scryfall search turns out Greater Good is the only no mana cost repeatable sac outlet in modern in GW colors that is an enchantment. Sadge

Lmao didn't see magnetic theft, nevermind

You can only equip at sorcery speed. Also, you can only equip things to creatures you control. "Attach to target creature you control. Equip only as a sorcery."

Id take out leyline from sideboard because then you can't use Lurrus as companion. Also put CMPN next to lurrus to make it companion.

Maybe Hateful Eidolon, and maybe Dead Weight as removal that synergizes with spiritdancer?

I don't think this deck wants to be playing discard to trade one for one.

but it would at least give a reason to run all lands besides flavor haha

I'm a little confused on the second line, why would Bottle Rocket sacrifice itself on ETB? If it dies on ETB you won't ever be able to trigger the attack and sac ability unless you have Stifle effects.

We need a legendary Cultivator Colossus

Manabase could be improved with more Watery Graves, Polluted Delta, Darkslick Shores, Drowned Catacomb.

I recommend adding more Murktide, just so you can slam down a clock faster. Maybe some Jace, the Mind Sculptor as well if you can afford him.

Hero's Downfall is kind of bad, I'd replace it and Bloodchief's Thirst with some Fatal Push. Path of Peril seems like a dubious choice of boardwipe since you can't even cast its cleave cost, and it tends to be very situational outside of Lurrus Decks. I'd cut both and go up a Damnation if you want more sweepers, then maybe put another one in the sideboard.

I would also definitely play 3-4 Snapcaster Mage, which is just an amazing card in any control deck, and could also help you win the game since you're so light on wincons.

General notes:

Running less lands increases your chances of flipping Delver--it also increases your chances of not being able to play any of your spells which feels like shit. 14 lands is insane, you probably want at least 18-20.

Cards like Unsubstantiate are bad because they are pure card disadvantage. Against spells that can't be countered its better to just let them resolve instead of running bad cards against them.

If you want the deck to be budget, just cut the Force of Negation. 1 copy isn't going to be doing anything the vast majority of the games you play, and its half your deck budget alone.

I highly recommend splashing another color. Blue has good card draw and countermagic, but lacks removal. Splashing red or black would be the best imo. Even though it does make the manabase a little more finicky, it should be fine as long as you don't run any cards with RR or BB mana cost. If you run around 8-12 cheap duals it should be fine.

Red would be for Dragon's Rage Channeler, Lightning Bolt, Unholy Heat, and Expressive Iteration.

Black would be for Fatal Push, Inquisition of Kozilek, Drown in the Loch.

I think aggro would be cheaper, but not having fetchlands to trigger revolt for hidden herbalists and narnam renegade hurts

Uhh around what budget? 100, 300, 500? And do you want to go more midrange or aggro

"I don't think *mana is a problem" is what I meant to say