I’ve found that as well with some files. At first I thought the issue was with the jellyfin instance had not enough capabilities, but after trying the same file with its subtitles, it worked on any other client: flatpak, web, and regular android. So for me it is the chromecast/androidtv device, so I am now looking what to replace it with

Firefox, with ublock origin and yt high definition plugins, so I can have a decent yt player. I have disabled/hide chrome, I have no need for it.

What are you reinstalling? New haos on old kvm? Old haos on new kvm? New deployment?

From the logs I read that your user chris has no rw perms within the haos.