If large companies like Apple and Samsung haven’t managed to produce non invasive blood sugar monitors then no one else will have made anything anywhere near accurate. And yes, it sounds like you are describing a blood oxygen meter.
I ordered one (stupidly) from Facebook advert. It was only an oximeter and did not read glucose levels. All adverts in my opinion for these type of products are scams. These meters do not exist NHS says so as well so do not buy however convincing the promises sound. I hope they choke on my money.