How do I ssh into a server over HTTPs?

I have a server that has a reverse proxy (NGINX) set up to host all my other websites/services on a single server. I would like to create a way to SSH into that server over HTTP. The reason I need to do it this way is that my server is running behind a VPN with port forwarding so the outside internet only has access to my server through a single IP and a single port.

I'm a little confused if this is possible or what I should be doing. From what I've seen I heard that I should set up an HTTP proxy on that server. Do I use SQUID for this?

Looking for some guidance, please.

The conventional method would be for an admin to establish his own VPN connection to the network where your server is to perform maintenance.

But there are tools that allow “protocol multiplexing” to allow you to connect with both http(s) and ssh (and other protocols) to the same port where subsequently the ssh protocol will be forwarded to your ssh daemon and your web traffic to your web server / reverse proxy : see for example sslh https://www.rutschle.net/tech/sslh/README.html