I like the strategic aspect. It's really fun when you succesfully dodge and punish, I like how some moves have indeed post-lag time and the other player can take advantage. You can even bait. I also like that when you land a punch, the animation creates distane again so that there is no exploitation. Really nice and actually fun, man!
Aparto from that, I'd say to fix the animations, some feedback I'd give is:
If you get hit: interrupt animation. I see some moves follow that, but I see it's only until a timeline point reaches. There should be more priority on stopping the animation the frame the attack hits.
Expanding on last point, with only one type of knockback, strategies can be formed to exploit combos really easily (My favorite is following up anything with a fireball because of the reach) If you implement different duration knockbacks depending on the move that has hit, this will be better for the recieving user to punish or come back.
The players should not share space with each other after a move. I tried my char to be always sharing space with the other and I was succesful, this lead to me always winning because most attakcs flew past me, permitting me do a combo with short attacks. Look at how SF does this and try to replicate it.
Don't do the deck idea, having all options is super nice, each charcater should even have a different moveset / card poll.
Map cards to specific buttons on a controller try that, It may be fun.
Not much more man, I think these are the main ones. Good luck!!