Any suggestions on securing SFTP and Game Instances?

Questions
1

Looking to secure access to game instance ports. Any suggestions? Proxy services?

I’m seeing that my SFTP ports on instances are getting hit. Would like to secure it, any recommendations?

I’ve limited portal access (443) to an IP whitelist/ or VPN users

2

If you can whitelist port 443 then you can whitelist SFTP (22) to a set of trusted IPs

3

I’m looking for a way to keep these public but to add a layer of security.