oximeters of like this are quite cheap only. accuracy is so-so
even my own honor band got an oximeter, but its only going to run when activated, not all the time. and its not particularly accurate.
it uses is light shining thru the finger to detect the oxygen composition in your bloodstream but this kind of crocodile clip is not comfortable to use for long time. and probably dont have logging (only real-time)

i got my own CONTEC CMS50F with finger probe (its like a watch with wire to attach to the finger) that can track overnight because of sleep apnea paranoia that turned out to be false.
well guess can use for kobis if needed.

probably not
probably too much caffeine just faks up my sleep.
logger doesnt indicate any drop in SPO2 and after cutting more caffeine i have more well-rested nights than before.

How much cpap? Where you buy?