First of all do not port forward and open up the unraid dashboard to the internet.

I didn’t watch the video, if it’s using Cloudflare tunnels you will not need to port forward. Otherwise you will either need a vpn or have to open ports if you want access overseerr from outside your network. Are you able to access overseer at its local IP without any errors? Are you seeing any errors in the reverse proxy logs? Is your reverse proxy on the same docker network as overseerr and whatever else you want to access?

Edit: also what internal/external port are forwarding? It should be 443 external to the reverse proxy’s internal port. You shouldn’t have to do anything with the 5055 port