

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.
Correct. Remote streaming used to be free. That changed…in April? I don’t remember the exact date but it was announced earlier this year and has been slowly rolling out. Now you either have to have a Plex pass for your server or each user who wants to remote stream has to pay for a remote watching subscription and show in OPs screenshot.
There are of course ways to get around this such as all your users being on a VPN so as far as Plex can see its “internal”. I suppose if you use a reverse proxy but didn’t pass X-forwarded-for headers then that may get around it as well? I never messed with it as I was looking for an excuse to dump Plex anyway. Now I’m finally jellyfin only.