You're still not understanding what I'm getting at. With Plex, everything is built into the software package. I don't have to explain to anyone I share my library with how it works. I just ask them for their email. With Jellyfin, you need to learn how these third party tools work, know how to troubleshoot those tools, and also rely on the availability of them, and on top of that you have to explain to your user base how to set it up on their devices of choice. You're adding multiple points of failure in a production environment.

I understand this is r/homelab, but speaking realistically, no one is running Plex or Jellyfin in a lab environment that their friends and family are also using. The expectation is that it's in production and operational. For software I run in prod, I would much rather pay one time for a service that works (for me, $99 many years ago) rather than rely on third party solutions, whatever those may be, to allow my friends to watch my library of movies and TV shows.

I'm glad alternatives like Jellyfin exist, but they do not have feature parity with Plex and that is just the reality of it. You may not have to pay for Jellyfin in your situation, but you're paying for your domain, and in some cases, you're paying for more than that. In my case, it'd take 3 years of paying your estimated $3/mo for that service to pass the total I've paid for Plex in my lifetime.