Help with ZeroTier routing between GL.iNet devices

The T-Mobile Home router does not allow port forwarding. Is that a problem with setting up a wireguard server on the home router?

Also I do not know how to export and or import files from the routers. I could use a MacBook Pro to do this? And if yes, can I use Terminal App or do I need other software.

You’ve been very generous with your explanations already. Your screenshots are great. Thank you so much.