I've found the best solution for that is spinning up an ErsatzTV docker instance and add the Live TV channel to Jellyfin. You can customize what gets played to the Live TV channel and I had used it to run a "kids TV" channel at home. The only drawback is I had to shut it down because the transcoding for it was brutal (on a server with no video card). It will convert everything to a standard stream format, and none of my video files would just get served as is.
Been using Jellyfin for a couple years now and it's been a blast. So satisfying to be able to keep my entire music library in one place and play it from anywhere. Sonixd is what I use for listening on desktop, and Finamp is what I use on mobile.