I have somewhat of a deviated septum, and even had surgery done half a year ago, but it didn't really change much unfortunately. I always need >=9 hours of sleep to feel good. I've slept on average 7 hours the past 2 weeks & I feel horrible (completely different reason for the reduced sleep). I did a sleep study a few years ago because I suspected sleep apnea, but because of anxiety or sleeping in a new place, I only ended up sleeping 1-2 hours that night. They didn't find anything, but I wonder if I should try again.
I have headaches but they are related to other sinus issues, though the doctor seems to think the CPAP should help. I’m not so sure but open to the possibility!
I do have a fitness watch though that can (supposedly) measure SpO2, and while that showed the occasional dip, it seemed more like a measurement error, and generally the values were in the normal range.
I also have had a finger pulse oximeter which logs and exports to an app via USB. If I sleep with that on it seems to be very reliable at recording the levels, the data certainly looks good and feels much more reliable than the Sense.