This is pretty easy with wireguard or tailscale.

Or - and I know people don't love this answer - just host it publicly. Yes - it requires some monitoring and a little bit of attention, but at the end of the day it's not that hard, and the risks are fairly low (even if it gets compromised - the world is not over).

Jellyfin has apps (which do incur a bit of overhead for maintainers in actual dollars) but honestly, as long as you're not on iphone, you can just build them locally and sideload them. No store/publisher required.

I primarily use the android tv client on a nvidia shield running a custom ROM.

https://github.com/jellyfin/jellyfin-androidtv