Do you see that images only use 100 MB in the debugger? That's very modest memory usage, it should not crash a phone with 4GB of RAM. The issue must be with something else. Try collecting LogCat logs.
If you need all cards (20 animations with 180 frames each) to be available on the same layout, then you’re right: splitting them into separate sprites won’t help.
The only real option (if the art style allows it) is to break each card into smaller pieces — for example, a shared border/background sprite used by all cards, plus a smaller unique image for each card.