Your history and the results of the sleep study would be the reasons for the recommendation for O2 at night.

I'm in the same boat and it has been helpful. Yeah, inconvenient and a little awkward, at first, but I sleep better and wake up more rested.

Are you living above 4,000 ft altitude?

“You must endeavour to enjoy the pleasure of doing good. That is all that makes life valuable.”
Robert E. Lee, in a letter to his invalid wife.