I play a similar list but without the land destruction angle and removing the black cards, more focused on early interaction with Abrade and Blink of an Eye and Banefire is my big finisher. Have you tried The Mirari Conjecture? It's such a powerful engine card for recycling removal and ramp spells, and the aftermath cards give it a lot of flexibility. Sorcerous Spyglass helps with control a lot out of the sb also, name whatever their main threat is (Teferi, Hero of Dominaria is generally what you're wanting to stop) and you can out grind anything at that point. It's cool to see someone else on a similar plan, I'm hoping GRN gives us some decent ramp, the guildgate things seem interesting in something like this but it would need a powerful payoff card to really consider it. I've started figuring out ways to keep the deck alive after rotation and have come to think that focusing on The Mirari Conjecture more heavily might be the best option. Good luck!

vomitpile I actually considered playing Banefire and conjecture, however, I wanted to have a solid control over my opponents' ability to interact with me. About half of the games I would wipe the board and then destroy lands and wait for my finishers. It got to the point where I didn't have to worry about my opponents and what they had because they couldn't even cast their win conditions. Now by the looks of it, I will have to revamp the deck considerably the black cards definitely won me a couple games with Ribbons or by bouncing my opponents win conditions and then making them discard those lol. I think Doublecast and the Izzet Guildmage both will continue to be very strong picks for this deck. I am waiting to see what Gate interaction spells there are if there is anything close to Hour of Promise or that interacts with having gates and getting tokens then Detour will be a must for this deck. 3G Search for two Basic lands or Gates and put them onto the battlefield tapped. I like Conjecture I just hate spending 5 mana for no instant effect. The fact someone can exile your graveyard in response to the conjecture makes me so cautious especially with how important the graveyard is about to become lol definitely interested in keeping up with each other through spoilers to see how things shape up!