So, Cricket is what’s known as a “reseller”. They’re selling generic AT&T service at a better price. It’s owned by AT&T and uses the same AT&T network/towers. It’s exactly the same business model as when Eli Lily sells their own generic of Humalog insulin and just renames it Admelog, even though it’s identical stuff.
So when you go looking for a new phone, you can pick ANY android device that says the word “unlocked” in the description AND either specifically mentions AT&T or GSM (Global System for Mobile communications, which is the type of cell network AT&T uses). A listing doesn’t need to specifically mention Cricket if it meets those 2 criteria. “Unlocked” is the magic word that means the phone will run with all sorts of different providers, not just a specific one. And GSM (or specifically mentioning AT&T) is the magic word that means that specific unlocked phone will work with Cricket, or any other AT&T reseller like Red Pocket, Mint, etc…
But more importantly, there is absolutely no reason to use a phone on Dexcom’s compatibility list. Dexcom’s hands were tied by the FDA, who don’t understand Android and the similarities between phones. Just about any android phone can run the Dexcom app, unless it was made prior to 2015. You just need Android version 6 or newer. And then you can install the “build-your-own Dexcom” app, which let’s you remove the device compatibility check.
Don’t worry, it’s really easy. You don’t actually need to build anything. You just answer a quick question are. I explained it a little more thoroughly in this linked post:
If you like your current phone and don’t want to change, then don’t!