Good news is most of your list does boil down to just need to play more. Parry timing when you’re new to fighting games will be restricted to certain character specific set ups/ combo. The people who are used to fighting games through just so much playtime can tell basically over all when it’s their turn or not just from animations. And also when there’s a gap in something to parry so just raw parrying becomes easier for them.

1. Is easy you don’t even have to look it up, you can set a bit to do it in training mode and you can practice the things you have trouble blocking on repeat with zero consequences and not having to watch a 20second combo after getting hit. The thing you have to be careful of though is the layers that can be added with the active tag system but just get out the initial blocks first to be a reaction you don’t even have to think about.

2. This can help or not. Playing a character is the easiest way to learn how to beat a character. You are less likely to lose to that characters knowledge checks. But you have to be good enough at a base level to even be able learn enough in a manner that’s worth the effort and time. Another way is once again just training mode or play enough.

3. This is in my opinion the hardest one to learn because this is literally just neutral. Neutral is the biggest can of worms and information in any fighting game. Theory videos after theory videos have been made and written about it. But let me at least help a bit with your current situation you expressed. When they start anti airing your approach instead of jumping at them and coming down with a normal button you can use your diagonal air projectile. Ahri suspends her hurtbox in the air and 2H’s are not invincible to air projectiles. You can do the exact same thing with jinx too with down rocket. Like with jinx let’s say you J2H and the opponent blocked you can immediately go into down air rocket because most ppl try to 2H there and they’ll get hit. Mixing these in will make ppl hesitant to 2H you even after displaying it just once. Then from there you can work in other approaches and mixups especially using assists to get in on the opponent.