Just lumping my experience in there as well. Also stuck on character select screen on steam deck, completely freezes up when I get to that point.
I'm happy to go through and try to document some troubleshooting to get this running on the steam deck, if someone can point me in the right direction for some log files or something I can look into.
I found this post which may be loosely related to this issue:
I'm apparently not quite familiar enough with the inner workings of linux to know how to follow the troubleshooting process they're going through, but if anyone could point me in the right direction I'll be happy to report back.