Bob :
Newer iphones (14 or later) have built in satellite sos capability
I have one and have use the test function but have not used it for real.
The next option is the satellite communicators. These include garmin inreach, spot messenger, zoleo, bivystick, and probably some others. I have extensively used garmin inreach and appreciate the two way non emergency communication. Cheap safety only plans are available. I have used this in a for real emergency and the results were not great.
The other option is a radio frequency epirb. These used to be for marine vessels but have gotten smaller so are worth thinking about. They cost $ upfront but no subscription and are only for emergencies.
Good luck! make sure to have one of these options, or just go old school with a check in person. BP