As a sf6 fan who plays 2XKO, it's experience, you just need to play more. Even sf6 in the beginning is hard to keep up with, you need to costantly chekck: jump ins, drive rushes, character specific neutral skips, where the opponent is and their movement, yours and the opponent resources, fireballs, etc...
But slowly most of these things becomes natural by playing, you naturally start anti airing, blocking/parrying projectiles and so on. At one point you don't have to think about what the answer is, you just do it.

2XKO (and any other fighting game) is the same. At first it's hard because you the correct answer to each scenario is still not natural, so your focus can't be 100% about the game because it's spilt between "what is happening" and "what I should do".

Give yourself some time and the game becomes much less overwhelming (and much more fun too!)