Before changing anything on your machine, working on sleep hygiene might help.
In this particular case, sleep hygiene relates to what you actually do under the circumstances you mention.
So, when you wake up in the middle of the night and can’t get back to sleep within 15-20 minutes,
then: take off the mask, turn off the machine, get up and out of bed and go to another room. Read something light (nothing about violence or politics or anything that is stimulating). Eventually (hopefully soon) you will become sleepy again (not the same as tired). When that happens, go back to bed, mask up, etc.
Rinse and repeat as necessary if the 15 minutes pass without going back to sleep.
What this will do is to help train your brain to the (new to you) habit of “I’m in bed and therefore I’m going to sleep.” Prior to developing this new habit, your brain was OK with being in bed and not being asleep. For example reading or watching TV, listening to music, etc. Got to stop all those things and make a new habit. For now , until you get this new habit ingrained, bed is for sleeping and nothing else. All other activities are somewhere else.