you are correct, inReach devices can text by themselves(with no cell signal) and can be paired with a cell phone to make calls(I have the 66i), but not make calls by themselves.
https://www8.garmin.com/manuals/webhelp/GUID-6E5DFD2E-EEE4-4...
https://www8.garmin.com/manuals/webhelp/GUID-6E5DFD2E-EEE4-4...