Get an EPIRB.
Just make sure you get one that uses 406Mhz rather than two-way LEO satellites. The two-way stuff requires monthly payments and is far less reliable, won't get through forest canopy. The 406Mhz SARSAT beacons are single use only one-way transmitters (they receive GPS, not 406Mhz-SARSAT, although they still work without a GPS signal). Anything that advertises using it to send SMS messages is junk for emergency use.
There's an older, lower-frequency SARSAT band somewhere in the 150mhz-ish range, but it gets so many false positives (like some ATM in Kansas) that it's basically retired. The 406Mhz protocol has a lot more checksums in it.
Edit: you want this: https://en.m.wikipedia.org/wiki/International_Cospas-Sarsat_...
Also, seeing on https://www.acrartex.com/products/resqlink-400 it says "Battery Replacement: After 5 years or after emergency use, whichever is first"
Speaking of packaging, the product you linked to is the buoyant version. Don't get that for hiking, it's significantly larger (physically) than the non-buoyant one. Confusingly, they are both called the "ResQLink 400".
It was a little nervewracking and spooky even though in truth I was only about a twenty minute drive from the edge of the park and civilization. To know that if I slipped and broke a leg or something I'd be screwed for a couple of days until a crew could find me.
But I experienced it as a good kind of anxiety. I deliberately wanted to get outside of my comfort zone and spend a little time getting comfortable with being uncomfortable. It was an absolutely rewarding experience and one of the highlights of 2020 for me. I woke up the next morning refreshed, centered, and excited to return home to my family.
A quote I think about a lot is J. A. Shedd's, "A ship in harbor is safe, but that is not what ships are built for."