Cool game!
A lot of interesting synergies to try out. A lot of content and a fun game loop.
Some suggestions:
I feel like I needed more information. Things like: What type is each card, how much xp do I have, a lot of cards would benefit from a tooltip with information.
I should be able to switch between cards of the same size.
Seems that taking a relic I already own does nothing, should at least be communicated.
all in all a surprisingly engaging game that kept me interested, well done.