Replacements: Vision for Leech, Aero for Kazar, Chavez for something
I don't recommend replace Magneto he is too good (Hulk is better in 5% of cases and Chavez or She Hulk probably win in that case anyways). Amor is good against Schang and Killmonger.
I hit rank 270 with this deck but both Meta decks (Surfer - Killmonger and Zabu - Darkhawk) are good against this deck (you have options like Aero, Magneto, Armor to win but you probably still lose in 60% of games)
I love this deck because you have lots of options so it requires some games to master. Snap when you have Quinjet and stones or Quinjet and Lockjaw. It's not hard win even without Lockjaw what I like about this deck but he is safest way to win. I recommend hold Space and Time stone for Lockjaw (until T3) these 2 are the most important stones. Lockjaw order: Space - Time- Mind-Soul-Power-Reality. Reality stone is sometimes the best and sometimes the worst if you don't need him don't use him it's too risky. Always use him as last card otherwise you draw lots of rocks or destroy other cards. Other Stones except Power (in Armor lane is safe use PS) feel free to use them in first turns without Lockjaw you are increasing chance to draw him (all stones except Power draw cards). Sunspot is great on early turns or for Infinaut She Hulk combo with Time stone on T4 (30 power T6 + Sunspot power T5) and waitting for Lockjaw (don't wait for him after T3). Time stone is good on T3 for Vision/Blue Marvel or for Aero if opponent use Wave you can expect Galactus or on T1 skip T2 She hulk T3 (but this is weaker combo with Time stone) or T2 Lockjaw but I prefer use TS in Lockjaw rotation. Space stone works base on location where he was (if your cards are moved with Bifrost or Strange Academy you can't move cards into location where he was played and moved) Blue Marvel can suprise opponent as last turn card for power push in lock lane and you have the most of time full all lanes what is good to counter Jugg/Aero/Magneto and he can be 5/14. If you played all stones and your opponnent stays in game and he can't win without Schang chi = he has Schang chi so sometimes don't play Thanos and play Vision which can't be destroyed. Thanos is almost never win condition but 18 power is 18 power.
Feel free to change every card in deck you probably discover stonger version.