Yes the most safe solution is probably using a VPN. But it's not userfriendly.
I don't think it's that unsafe to port forward the RTSP stream of you camera. You don't want to port forward other services from your camera. The main problem is that most camera's won't get updated for more then a...
I assume you run Nginx inside Docker.
Go to Status > Connections and you will see that all connections are made from the IP address where Docker is running. Since Docker is inside your network, all the requests from the webserver will look like from inside the LAN.
I figured this out just 5...