Yeah, that's in the log files themselves, it sounds like those messages are harmless (it's the generic Steam logs, not the Proton game logs) even though there's some weird encoding going on there I suppose.
o_O  Non-potato edit to make it clear these are two different screenshots and taken in case it's a font thing ...
on my manjaro amd laptop it runs ootb with 6.3-6 this error looks interesting: Could not connect to X session manager: Authentication Rejected, reason : None of the authentication protocols specified are supported and h