hides as regular HTTPS traffic so it’s not blockable by Firewalls

From OP's post, of course. If OP does not need to evade firewalls that are that aggressive, then they should have settled for a less stealthy VPN solution, as many of these HTTPS proxy solutions have performance and usability (can often only proxy TCP traffic) tradeoffs.

Perhaps they have already tried the wireguard on port 443 solution, and it didn't work for them. My high school would auto detect and block wireguard to any port. Perhaps they are in a similar situation.