Continuous Glucose Monitoring

I believe these cheaper devices are not very accurate ie accuracy range of 20% which is a fairly wide window. I’ve also heard there are many things that can impact your glucose even with the same meal like time of day, exercise, stress, sleep, etc. So if you actually want to find the patterns you’d need the expensive CGM over many months.

Is that true? I have no perspective but it's relied on by diabetics and if since they can't regulate it themselves, if the readings are off and they gave themselves insulin, they would know it is wrong. Maybe the OTC ones is different than the diabetic one but I didn't think so

They're not any different. CGM's have issues- sometimes need to be calibrated against a finger stick (officially, they always need to be)

In the end though- it's still a bit of fungal extract painted onto an electrode, and an ADC that reads the value every so often. Like any other glucose monitor.