Oh, maybe I misunderstood? It sounded like he didn't understand what advantage a "tunnel" could provide.
If your server is behind CGNAT, you need a TURN-style "tunnel" to allow incoming connections. If you have your own remote server with a public IP, then you can absolutely use that and create the tunnel using wireguard (or openvpn, ssh, etc).
I just mentioned CF in my blog post because it's probably the most popular solution.
The point is, if you have CGNAT, you need to create that "tunnel" somehow if you want to allow incoming connections.