I’m in a similar boat, switched from Android TV clients to a couple little beelink N100 boxes (which are great). I use Kodi as my Jellyfin client which works great especially with a remote/from the couch, and a cursory search would imply that Kodi has plugins for Prime Video and Disney Plus, but I don’t use those, so I have no first-hand experience.

The big one that annoys me right now is the lack of a TV interface for Spotify outside of the walled gardens of Android, Apple, and Roku. The desktop app does not play well with anything but mouse and keyboard.

Another thing to note is that Jellyfin Media Player plays really nicely on a TV/Remote control setup.

I used this version of Jellyfin for a long time and had no significant issues. The maintainer usually had new versions available within a week.

Don’t do it. I did it for a while it’s very slow and hard on the weak little CPU in the router. Eventually the USB port burned out entirely.