My Garmin 245 Forerunner does.
It doesn't automatically detect sleep but I set a time.
It will track movements, heartrate, SPo2 and breaths/min.

I don't know much about Apple watch but last time I checked my Garmin heartrate it is accurate to the machine doctor and nurses use.

I am new to the forum and new to CPAP. I started using a CPAP pre-diagnosis at the recommendation by a friend who uses it too. I bought an old Resmed Spirit S8 that was a bit erratic and very noisy . I upgraded to a Resmed S10 Autoset and bought a full face mask. I slept much better with the machine...