Setting up Reverse SSH Socks Proxy Tunnel or Openvpn Node from inside my schools network

I’ve had this idea where I use some of the raspberry pi’s I have laying around as Openvpn Nodes or a machine that’s inside my schools LAN.

So obviously the question here is HOW can I facilitate dropping a Pi on a network that’s either public or I have only the wifi password for and be able to connect out to the wlan? (no admin privs)

Would it be possible to change the SSH port to 443 or something like that and be able to connect out that way?

This is my first post on here. I would really appreciate any feedback. Thanks!