Congrats
Forget their preferred app. Try Glimp or the other free libre app instead.
It has a few flaws, but basically, the thing is a godsend, that the NHS should be providing (at least, as a cheap substitute for a CGM+Pump closed loop system) for every diabetic.
The thing is... it's subtle. For all the up-front benefits like not having to prick your finger to know what your BG is, I find the real value is more long-term: not getting single readings, seeing trends, and seeing them day after day, until you gradually gain a much better understanding of the disease, of food, of insulin, and how it's all affecting you.
The Libre gave me the confidence in my BG's necessary to experiment and improve my health. Without that confidence/situational awareness, I might never have made the previously insulin (basal reduction etc.) and diet (keto) changes necessary to affect real change in my wellbeing.
Hell, I probably would've felt so self-conscious about my "bad" readings that I still wouldn't even be telling healthcare professionals the truth, never mind actively consulting them and taking charge of my own wellbeing.