I have same problem.
get a gadget called the O2ring. google it.
It fits on finger like a ring so it stays on, even while sleeping.
It records the O2 reading every 4 seconds and can keep 4 10 hour sessions in memory. It also displays real time on your phone. can save data to phone and you can plug it USB to computer and download data and display it in various forms. Very well worth the money, since doctors only get a small snapshoot of information when in the office.
Can be, positional, when lying down, which doesn't happen in office.
My O2 was always weird and eventually would eventually get to 97 and docs say ok.
Ring showed my O2 fluctuates up and down 10 points every 40-50 seconds.
While sleeping it can go to 72 and sometimes stays low 80's for a few minutes. Still working with sleep study people to figure out what is really happening. I'm fighting with them on calling it Obstructive Sleep Apnea because I could be resting, lying down, and breathing at normal 15-20 breaths a minute and watch the O2 go from 97 to 87 within about 30 seconds and back up to 97 the next 20 seconds. Like clock work, all night long. When up and about it looks kind of normal slowly variying high 90's
I have appointment with 2nd sleep study doctor next week, Feb 2024.
Hope I can get better information.