See whether you can use the Add button on the APN page to configure the APN manually as this troubleshooting guide Pixel 7 unable to connect to mobile network despite valid SIM/eSIM - #2 by aibd.
There is also a higher level of defining your contact with the carrier. Please follow this link to check your IMS registration is complete.
Proving your IMS registration identifier starts
22250
then this provides
mcc="222"
mnc="50"