Sleeep tracking with CPAP

I have a Galaxy watch 7, and sleep tracking has been mostly reliable.  I started using a CPAP machine about 10 days ago, and since then my sleep scores have been substantially lower.  Before, I routinely had sleep scores above 85.  Now they are 50 to 70.  And yet I feel like I sleep at least as well as before.  With fewer apnea events, I would think my sleep (REM, deep sleep, etc) would be better, not worse.

I should note that I took to the CPAP like a duck to water.  I'm totally surprised.  I've worn it all night every night since the first day.  So I don't think the CPAP is keeping me awake.

The big complaints in my recent sleep score has been increased awake time, and lower scores for REM/deep sleep.

So my question:  Has anyone else noticed any similar trend, sleep tracking with a CPAP?

Thank you!