Jellyfin version: 10.5.5 on Windows
I’ve been having an issue with playback for 2 shows (Community, and How I Met Your Mother - both are amazon web rips to my knowledge) the error message is “There was an issue with the client profiling and the server isn’t sending a compatible media format.”, also there is no image or artwork for the shows. To fix issue 1 I tried playing in both the web client and MPV Shim client, they didn’t work, they work in VLC on desktop and VLC through android tv app external player feature, I eventually tried renaming with sonarr to make sure ti wasn’t a naming issue (as they had different naming schemes compared to rest of shows) it didnt work, it plays properly with trans coding on, however I want to avoid this as Jellyfin is currently running off my main machine and I don’t want to use up all my CPU resources to watch shows.
Edit: I thought it was a metadata / naming issue because of lack of artwork / image
I got the same issue with my entire library on Raspberry Pi 4B 4 GB 
Unfortunately it seems that TheTVDB changed something a couple of weeks ago, such that no new series added to Jellyfin will get their artwork (though metadata still seems to be coming through OK). I solved this by manually finding and adding images, and crossing my fingers and toes that they revert their API back to the way it was (or that the Jellyfin devs figure out what happened and change the scraper accordingly).
As for the media format, run MediaInfo on a few of the files to find out what CODECs they’re using for both audio and video - it may be that they’ve been encoded in something exotic like VP9 (which VLC will happily play but most other players won’t). If this is the case, transcode the files into something more standard (x264 or x265 with AAC audio would be best) so they can be direct-played in future.