The thing with this one is I feel like I am only playing the game when selecting the upgrades. The rest feels like I am just watching the plinko chips fall and I have no influence on it, and am just sitting there waiting for them to fall.
I think to improve it you can consider that you can influence something about how the chips fall on your end or opponent's end rather than just sit, wait and watch them fall. I also felt the same way about the part where I think they are fighting? I think it's supposed to be an auto attack but it feels like just waiting to me. You should consider similar core enhancements for that too.
I think at bare minimum, there should be some way to increase the speed of these passive events by holding down a key on the keyboard or holding down mouse click, so player can get to the parts where they're playing, but probably it's not enough IMO.
Overall I thought this concept is very interesting and has lot of potential. I like the two sides and the plinko chips falling at the same time in real time. I think there may be a lot you can do with that. You could have have something where the player (not sure what for now) influences either your side or the enemy's side while the plinko chips are falling. A similar idea can be done for the battle, but again, not sure exactly what at the moment - it can be for you to think about.
I don't see anything like this reflected in your GDD under "Beyond", instead it just says extra weapons, more cards, more effects. But how is that supposed to help if the player's still sitting there waiting for a vast majority of the game and all they do is pick cards when they are playing, and that's only like after waiting for all the passive events?
Overall, nice job on this because I think your idea may have potential.