How often do islanders talk about the "sweet spot" in their house, where they get best cell reception ?
You may want to consider "WiFi Calling" (we make no representations nor take any responsibility for any of this).
But, there are some islanders that use it.
Basically, your phone links to your WiFi, which connects it to your cell carrier. So if you're Internet routers provides wide coverage in your home, it might be less "fussy".
Here's a couple of links which might help you.