I have played the game and given feedback here:
It maybe still uploading, hope this helps you a lot.I also stole your graphic to have as a thumbnail, I hope that's ok.
Viewing post in SlayQueen: The Gatekeeper jam comments
I see, I think maybe you need to have that main screen to the left say "All cards" or something as simple as that, in between the deck and the cards you could have an arrow that points right too, that would help a lot.
I'm not sure how much of my feedback was helpful, they're just thoughts as I was playing, hopefully it's in a style of a todo list.