Let’s Encrypt are rolling out IP-based certs, you may wanna follow its development. I’m not sure if it could be used for your forwarded VPN port, but it’d be nice anyhow
Edit: I believe encryption helps prevent tampering the data between the server and user too. It should prevent for example, someone MITM the connection and injecting malicious content that tells the user to download malware
Thanks for the guide. How did you get the VPN forwarded port? I believe this depends on the VPN provider’s software?