Cellular phone reliability is pretty low as you can travel and find dead spots. This has nothing to do with the make of the phone.
Given your words here your employer should set you up with a satellite phone. Those work where cell phones don't and there are other considerations but given what you wrote, it's the only way today.
I worry also about your question of support. Almost have gone to pay as you go support. It's rarely included with your Apple experience being the exception.
I have a job that requires a functioning smartphone at all times, one that cannot break and especially cannot break for a long duration of time. This is why I stuck with Apple Iphones for so many years, because of their reliability and the abundance of Apple Stores.
I am currently using Samsung Galaxy S5 and am thinking of switching to a Motorola phone when my contract ends, I prefer Andriod phones and I especially like that it is cheaper and does not have as much bloatware. I am concerned, however, about Motorola phones' reliability and the strength of their customer service.
I have to have a smartphone functioning at all times, and I would pay for the higher price for an Iphone just to have the assurance that it will always work or be quickly fixed. So, how reliable are the Motorola Smartphones like the Moto G4 and how good are their customer support services?

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