

I don’t know how developed your school system is but, I would advise the principal into blocking the websites via DNS that way the computers won’t resolve them.
AdGuard, PiHole, OpenSense are free open source DNS resolvers however, chances are your school already manages its own DNS so I would obviously consult with them first.
My ASUS WRT router running Merlin firmware offers to host a WireGuard server, I simply use the WireGuard app, dump the config file in and hit connect.
Took a little configuration but eventually got it working how I want it.
Edit: Reason for the Merlin Firmware is because I can route my VPN server through my VPN provider, goes a little like this;
5G/LTE > WireGuard to my router > Router routes that connection to ProtonVPN
This gives me access to the resources in my home while also reaping the benefits of my VPN provider.