Did you ever find a solution for this? I tried the T-Mobile 5G home internet today, and it was great except that my Z3 didn't work. It was strange, the Z3 showed connected both on the LED and on the Meraki console and was even able to run a throughput test. When I tried to connect to the wireless, it simply would never connect.
The event logs showed 802.1x association and disassociation and BGP was bouncing all over the place. I threw my Xfinity modem back in the mix, and immediately back in business. Guess that's why T-Mobile internet is only $50.