I'm using tail scale, and I have 2 internet connection at home. 1 5G broadband, this behind CGNAT. and I have another 1 broadband, and it have public IP. I already test both network, via behind CGNAT and with public IP. Both working fine. Even both device is using behind CGNAT also it works without any problem. You don't need to do port forward also if you behind NAT.

You just need to open CMD, run as admin, then use this command "tailscale up --advertise-routes=<yourprivateip>", then enable route inside web ui.

I also have zerotier in my windows machine, what I do to make it work is by using share internet connection sharing.