I put a Quectel EM12G modem into a WG3526-P router and used my calyx SIM. Works great. No real special changes needed.

https://thewirelesshaven.com/shop/routers/lte-routers/wg3526-p/
https://thewirelesshaven.com/shop/modems/quectel-modems/quectel-em12-g-cat12-m-2-modem-2/

Needs an adapter and ...