Since this would be the phone number that you’d rely upon to have continued access to those government services, I wouldn’t skimp on the expense: consider the monthly charge for a domestic phone plan as a cost of citizenship or residency.

Supposing you find and set up an eSIM with a domestic carrier in that country, then one which supports WiFi calling would allow you to receive SMS/MMS from anywhere, provided that your phone also supports WiFi connectivity.

As an aside, WiFi connectivity was greatly useful when I was traveling in Japan, since I’d be back at the hotel with WiFi in the evening, which conveniently overlapped with USA West Coast time, so calls were perfectly natural.