I was really struggling with infinite this month but Shuri Sauron was the answer all along
https://gamefaqs.gamespot.com/a/forum/b/b030d5b6.jpg
For most of the run I was using Nebula and Juggernaut instead of Shang and Enchantress.
Juggernaut wins a lot of games on turn 6 because nobody expects him but ultimately I needed the counters for Miss Marvel and big destroy cards.