Well I already have jellyfin running in a container, just have to figure out how to get mum's TV to work with it I guess
log in on a local IP and not the network name and it's working again. but I'll be moving to jellyfin from now
Yes, however using the relay is not a prerequisite to being required to pay for a Plex subscription. That is what he is trying to say.
I can run Plex on the open internet and not use their relay at all, however if the IP of the viewer is not an interal IP on the same subnet as Plex (I assume the same subnet is required) then you'll be greeted with the Plex paywall.
You are absolutely correct that it costs money to run a relay, but the relay has nothing to directly do with the paywall.