Making games is hard! Especially in one week, or less!
I've also run into issues exporting for web players. Yes, it seems like scriptable objects are one of the problems with Unity exports, mainly due to the way the compiler compresses.
The card mechanics do sound pretty cool and would have made this game pretty interesting. Unfortunately, the build didn't work.
Collisions can be tough. There are a bunch of ways you can go about implementing it. For a game like this, my instinct would be to start with tilemap collisions. But that is definitely not the only approach.
Personally, I find that I learn the most from being ambitious and pushing myself. The important thing is to just keep learning and have fun with the process. If you enjoyed making it and felt like the working build was fun to play, that's half the battle. Keep making games.
-Morgan