This is an odd coincidence. I'm seeing my doctor for this tomorrow. As a scientist, I'm big of reproducible, objective evidence, so I used 3 different types of SPO2 monitor (Galaxy Watch 5, Wellvu ring, and the Welvue wrist/ring combination. All 3 show the fluctuations, and 2 that I ran together match. I have printout data from both. No symptoms at any point, range 71-100%.

Check your blood pressure, if you havent already. Mine is just as nuts. Pulse ranges from 42 to 150+,
It's real, and you are not alone.