I’d be interested to hear more here - what CGM did you buy? What was your process for monitoring?
The app is subpar on iOS, but if you give Apple's Health app permission, you can get more data in there. Graphs that have absolute numbers. I think they reason their app doesn't give absolute values (for historical values, they give the current value only), is because it's not a calibrated device. It can't be used to control an insulin pump, for that reason.