We are also changing how remote playback works for streaming personal media (that is, playback when not on the same local network as the server). The reality is that we need more resources to continue putting forth the best personal media experience, and as a result, we will no longer offer remote playback as a free feature. This—alongside the new Plex Pass pricing—will help provide those resources. This change will apply to the future release of our new Plex experience for mobile and other platforms.
Authentik + jellyfin SSO plugin?
I haven’t tried it out personally, but I use authentik, for that you can just create a password policy, then add a new stage for identification (just make sure to add the email field), and an email stage, then create a flow.
More work on your end than paying someone else obviously.