A found a few of things that really helped back when I needed a CPAP:
1. A pillow stuffed with buckwheat hulls. It holds whatever position you put it in and doesn’t interfere with the tubes and head strap. They’re expensive though so I made my own by buying a 5 lb bag of hulls online and dumping them into a zippered pillowcase.
2. Xylimelts, those little discs that prevent dry mouth all night.
3. Medical tape to keep your mouth closed at night. One small piece is enough, and easy to remove.
Also, If you’re swallowing a great deal of air your pressure is probably too high.

I had a love/hate relationship with my CPAP. I loved sleeping soundly, no longer gasping my way out of apnea nightmares, and the end of those morning oxygen deprivation headaches. I hated all that apparatus and the PITA of arranging it nightly. I am very lucky that after losing 45 lbs (4 years ago) I no longer need have sleep apnea.