I have been using kodi but it just so limited and clunky. Android TV is better but that is a major challenge since Android TV is very tied to Google with not much existing outside of Google.
What I am looking for is a device that can work with mostly Jellyfin. I don’t use any streaming services. It would need to work flawlessly with a remote and I am looking for something that maintains itself mostly.
How “big” are your movies and tv shows? If they are 4k UHD remuxes then Nvidia Shield Pro or Apple TV 4k behind a firewall to block external internet is your best option for performance, usability, and privacy. You will want to ocassionally allow it internet for software updates. Kodi, a mini pc, raspberry pi, etc. would be more private but you trade off a seamless remote, easy interface, and streaming codecs (e.g., dolby vision).
The Nvidia shield can run Lineage which is a option.