

There are two types connection in this scenario
- Direct - no additional cost to Plex, using the port forwarding instructions you mentioned. No limit on bandwidth - the best (and most common) option
- Relay - for whatever reason your client cannot reach the server (CGNAT / port forwarding not possible / firewall on client side etc), Plex will act like a man in the middle & limit the connection to 2mbit. (Yup, megaBIT).
I switched away from Plex last year because they wouldn’t let me connect with my box in Hetzner. I’m now using Emby, ironically I’m also paying for Emby’s monthly subscription. Not because I believe I need to, but because I want the developer to continue to work on it.
It was Plex that did the IP range ban because people were selling access to their boxes.