I'm just rewatching this video and I have a feeling that there should be some kind of Monarch deck that's really good against Chaos. There are just a lot of things that line up well. Your Monsters are bigger than theirs. Neither Return nor Decree are that great because of Mobius and your small trap lineup. You also don't fuel the opponent's Return, which I feel like this Chaos version in particular would struggle with (part of the reason why I think it should run 3 Decree. But I also really dislike 2 Decree decks in general). Thestalos makes it harder to hold Sorcerer etc. Monarchs were barely a thing during this format, but I feel like they are at least better than that.