They work, need a good sight line of the sky. Globalstar had a bad name years ago, but not sure if that is still true. They never worked south of of Iridium was what we were issued when overseas and in places where cell phones were not feasible.
But I base this info on history over 10 years ago.
But I understand your worries, since I'm single and hike a lot with and without the dogs, I carry a Personal locator beacon (aka Emergency Position Indicating Radio Beacon EPIRB).
Simple device, costs about 275, one time fee. Register with NOAA for free; but actually not required. They will work in places a SPOT location will not work, but a SPOT is better than nothing.
When working with the SAR, if asked, they would recommend a PLB over a SPOT, but again, that was quite a few years ago now.
It send out a a satellite signal, but also has a homing beacon and flashing LED light. Sat signal gives GPS, low level is used by most SAR units for pinpointing a person. Be surprised how far people can move away from the first signal with GPS, and in the dark hard to find so the homing beacon helps, along with the bright flashing LED.
I believe they even offer some non-emergency tracking features like SPOT, but never opted for that service.
Battery is good for about five years, then can be replaced, or just a new unit purchased.