There is a build your own for Android which bypasses the compatibility check and it’s worked on several unsupported phones for me
On iPhone I’ve not had any of the later models not work and I’m running the iOS 14.5beta
I quite liked the tandem handset
However if you can get a go or consultant to prescribe something it’s most likely to be the libre in which case getting a Bluetooth add on if worth it. And while not quite as accurate as the Dexcom millions use it and are happy with it. And it will certainly give you more data than you have now