In case it helps anyone else that is confused by this, I noticed that on the login screen for the router you have the option to login using your TP-Link ID or just using the default admin/password...

I am having the same or similar problem. I just purchased and installed a TP-Link router: Hardware Version: Archer A7 v5.0 Firmware Version 1.0.10 Build 20190517 rel.65170(5553) I logged in with my...