I also have been using dreamstation because it is the quietest among the cpap machines. The issue was the foam that was used to dampened the sound. It would react to some ppl using O³ gas as a disinfection method. This causes the foam to release carcinogens. Philip had a worldwide product recall to replace the foam and motor FOC. Go back to your seller to get this. I did mine 2021.
Using CPAP, I didnt have any more awakening from apnea. My AHI was borderline 28. But subjectively I felt much better.