You are aware that this isn't a lifelong commitment, right? A Plex license doesn't make using it mandatory. In fact, had you read a bit further, you'd have seen that it's no commitment at all, and I'm still running and maintaining a Jellyfin server simultaneously, reverse proxy and all. Not just as a fallback, but also for the things it still does better.

I migrated my household use to Plex, though, because this evil "closed source for profit app" offers an on-device user experience that is as good, if not better, than that of a commercial streaming services. This makes the rest of the household use it happily, instead of seeing it as an inferior alternative.

Jellyfin's user experience is simply not there yet, not even close. Its clients, if available at all for the system in question, are (mostly) functional, but certainly not fun.

I had the money to spend on the evil "closed source for profit app" and it made my family's life a little better for it - are you sure that trying to shame me for that was the right reaction?

Jellyfin requires a reverse proxy or similar to be reachable from outside the network, once that's set up, the usability gap between the two becomes a lot smaller. And Jellyfin does, still, have some benefits over Plex - first and foremost: it doesn't require an active Internet connection and an "ok" from a central server to fully function - it also has fewer restrictions when it comes to sharing content and a better plugin ecosystem.

Again, I think both are highly capable servers and I'm running both in parallel, even after migrating most of my personal use to Plex.

It's the clients where it all falls down, sadly. Jellyfin's are, even after all these years, clunky, ugly and unpleasant. The choice of supported devices and systems is also quite limited. This is where Plex shines: they have a, generally excellent, client for pretty much everything you would ever want to play your media on.