I was diagnosed to moderate sleep apnea in March this year and the ResMed CPAP device was my savior. My life truly changed after that , which I think was impossible. I wake up refreshed like I used to do when I was a kid.
A couple of months ago, I purchased another device (a headband to be precise) called Dreem2. It is manufactured by a French startup. I had to make a choice between Oura ring and Dreem2 as both were expensive. But were equally good as far as quality of tracking is concerned. But I chose Deem primarily because in addition to tracking, it also enhanced deep sleep by inducing pink noise (not via earplug but innovatively directly via the bones). And Dreem is the only consumer device I have known so far that measures sleep state from your brain activity via EEG (which is the most accurate so far). Check their website (dreem.com) if you are interested. If you make an informed decision to purchase it, you may use my referral code ( BXNDWKQRO) in order to avail a 20% discount. I do not have any other affiliation with the company apart from being one of their happy customers.