

I’ve never needed to do this but have you looked into creating a Reverse SSH Tunnel? Maybe that can accomplish what you want https://www.howtogeek.com/428413/what-is-reverse-ssh-tunneling-and-how-to-use-it/
Similar to what you are trying to do - A while back when I needed to remote connect to a firewalled Windows computer I set up a reverse VNC connection on that Windows computer that would get initiated whenever I sync’d a file over to the Windows system via Dropbox/Syncthing (those work without port forwarding). Reverse VNC, like Reverse SSH or other connections basically try to initiate the connection out of the firewalled system, it’s an interesting workaround when you have no incoming port forwards. Not sure if I’d recommend that type of set up but it is more secure than sending emails so there’s that.
If you’re able to set up a mesh VPN that might work better but you do have other options if you need them.
Yeah I was going to say the same. A year ago I couldn’t get any VNC to work under Wayland and gave up on the idea, nowadays just use RDP (Xrdp, Gnome RDP, etc.). I don’t usually need screen sharing specifically so RDP fits my use case perfectly.
But it’s great to see VNC catching up, more remote options are always better.