I think anything safety wise it is a smart thing. If you want to be off-grid then just turn phone off right? But as far as boosters or things like that, you know more than I do. What I wanted to mention was this was a concern of mine as well. I would bring just good old fashioned walkie-talkie's, still work great and they have more range than you think.
But what I also wanted to mention was I was going to get an expensive satellite phone but needed to upgrade my iphone coincidentally at the same time. When I did the upgrade, I found out the new iphones (17 Pro in this case) are satellite capable through Verizon.
AI Google Search- "The Verizon Apple iPhone satellite feature (part of Apple's Emergency SOS & Messages via Satellite, available on iPhone 14+ with iOS 18+) works by automatically detecting no cellular/Wi-Fi, then guiding you to point your iPhone at a moving satellite overhead for short, text-based communication with emergency services, friends, or for location sharing, using a network partnered with Globalstar, allowing you to send crucial messages from dead zones with a clear view of the sky, though it's text-only and slower than normal.
The Satellite feature came on when I was out of range just like the AI search says, I pointed it up in the sky and it worked as promised. I think T-Mobile has this feature available too on iPhones but you will have to research that a bit. I'm no expert at this by any means, just sharing my experience. Good luck...Enjoy the UTV.