I had a similar issue where I wanted to use my Xbox Series X to play Jellyfin but there was no client available. I ended up switching from Plex to Emby. I tested it for a month and then bought a lifetime pass, I’m quite happy with it. The client definitely isn’t as polished as Plex’s clients are but they allow me to do everything I want with much more control. I especially like the plugin system, being able to create my own persistent 24/7 faux tv channels is A++