I think this is whe you'd look at nit having a sim at all. Ethernet to router when possible, otherwise ethernet to a 4g dongle.
Make sure the sim in the dongle is prepaid and not associated with any accounts in your phone (WhatsApp registration etc).
Have your public facing number in a dumb phone and turn that only for select 2fa and ss7 calls when you have no choice but to attach to normal network. Be aware of cell tower triangulation at these times.
The sim in your dongle should be prepaid and un registered. Only feed info from device that is encrypted on device.
Your carrier will only see encrypted info from your hotspot. Anyone targeting you for sim attacks with your public facing number will end up in your dumb phone sim. Even if they do aquire your dongle details, they shouldn't be able to extract phone data, only dongle data. As your hotspot dongle won't have gps all they can aquire is tower data.