It's saddening that most of the reasons the games won't work on deck is due to anti cheat. Personally I'd love for destiny 2 to work on deck but I believe that they're using more than just battle eye which is why they can't just enable it for Linux.
They have/had a linux stadia port working so they technically could get it working on linux, but bungie have always been anti-linux so it's most likely not technical challenges.