If Linux was that easy, adoption would be higher
People use what comes on the computer. OS usage on the Steam Deck is overwhelmingly Linux because that's what comes on it. This indicates that Linux is perfectly fine for the average person, it just needs to come pre-installed. Very few people install their own OS either way, Linux or Windows.
If you're waiting for Jellyfin to run some kind of relay like Plex, you'll be waiting a long time. That takes a lot of money to upkeep, and the demand for people who self-host FOSS and then want to depend on an external service is very minimal, certainly not enough to sustain such a service. I'd recommend just spending a weekend afternoon learning how to set up Nginx Proxy Manager and being done with it, the GUI makes it very easy.