Similarly, my Belgian ISP (Telenet) has WiFi home gateways that are configured by their web portal, and config is pushed by the ISP.

I figured out that they only did validation on SSIDs client-side, so managed to get around that to put emoji's in my SSID.

Which then proceeded to soft-brick the entire thing on config push. I'd have to log in to the web portal via another connection, change the SSID there, and then reset the hardware with the reset button to get internet working again.