I kind of feel like by A2 I’d have figured out where the optimizations are, and it’s just a matter of finding them, not sure if I’d have the energy to actually try them in game.
No, that's backwards. On low difficulty you can indeed force a strategy chosen in advance, but as the game gets more difficult you need to make choices that trade off the late-game power of your deck against the needs right now (so you can get to the late game at all)
To transliterate your comment into an equivalent context:
I feel like after 12 or so hours of chess I'd figure out how to not hang pieces. From there, how to find the best moves is just a question of dedicating energy into finding them in game.
I'm not sure why anyone plays more than 100 or so hours of chess. Doesn't it get boring?
Until you've actually played at A20 it's hard to understand how different the game is. There are picks for cards, relics, shop purchases, etc, that are absolutely crucial to get an A20 heart kill that you would never even consider picking at A2.
You could always "cheat" and skip straight to A20 (I assume there is a way to do so, at least). I find the difference between low ascension and A20 to be rather large, so while it's true that optimal play at A20 will work at A2, I'm not sure I was capable of that when I was at A2.
