No idea about the connection issues.
If you’re referring to the Plex Relay service, the bandwidth limits are documented, not hidden.
When using Plex Relay, Plex Pass users are limited to 2 Mbps. Non-Plex Pass users are limited to 1 Mbps.
If access via Plex Relay is causing issues for your server, you can disable it in Settings → Network (Show Advanced). This was introduced with PMS 1.18.5.2260.
https://support.plex.tv/articles/216766168-accessing-a-server-through-relay/
