Reverse proxy problems when using VPN, but not when using a reverse SSH tunnel

[schnappi]

Jellyfin server is behind a Carrier-grade NAT with no port forwarding. Using an Nginx reverse proxy to access it. The reverse proxy works perfectly when using a reverse ssh tunnel, but here are issues (sometimes slow to load, videos stopping randomly) when using the VPN as the reverse proxy source. Tried changing the MTU of the VPN on both ends, this did not resolve the issue. Curiously, the same issue occurred over both a Wireguard VPN and ZeroTier.  My theory is that UDP (Wireguard and ZeroTier) are never going to work behind this particular cgnat, but TCP (SSH) will. At this point, have given up on a VPN and am using an automated reverse SSH tunnel. Any suggestions are welcome.

[williamthrilliam]

Are you trying to use VPN and a reverse proxy? Why?

[schnappi]

The Jellyfin server connects to the server hosting the Nginx reverse proxy via either a VPN or SSH tunnel.

Jellyfin Sever (cgnat, cannot open ports)----------(VPN or SSH tunnel)---------->Nginx Reverse Proxy Server