If the creature is removed, you lose card advantage
If you want at least an 80% chance to hit 4 land drops by turn 4 then you need to bump the land count to 39-40

In Kaladesh season, the average set power was too low and some OP cards were messed up, and as a result of gradually increasing the set power to make up for this, the Eldraine season was a total mess because the set power was too high.[17] As an aside, the 10 chapters that were banned from the standard at that time were Tolaria Academy , Dream Room , Windfall , Earth Manipulation , Shifter , Lotus Leaf , Persecuted Nightmare , Time Vortex , Thought Force , and Memory Jar .[18] Banned 52 cards printed in 2019-2020 in all formats combined[19] Inherited the vintage restrictions of August '94.[20] It was banned 14 days after release, holding the record for the shortest ban in Standard.[21] As an exception, it could be used if the event deck that contained Stoneforge at the time was used without modification.[22] It was initially announced as no change, but was urgently banned two days later.[23] Unbanned with 1 month left in rotation

In terms of phases, I need to do something to reduce my graveyard if I only have Repentant Vampire and Dystopia in play so that I dont have threshold on my opponents end step, or Ill have to sacrifice my Vampire
A lot of the options have blue or red as central colors
Sapphire Medallion can be particularly strong in multiples, building towards a Capsize-lock endgame (bouncing two or more lands a turn on their end step to keep forward progress going without risking anything)