- Sleep propped up. I did this for several years. It was not an ideal solution, but it did provide improvement. I got two large, different size wedges, used one, then other and then both together. Eventually, I bought an adjustable bed.
- Lose weight. Many folks report good results from this. It did nothing for me.
- Oral Appliance (aka, dental appliance). This works for some people, but the main, undesirable side effect is TMD (which happened to me).
- UPPP surgery. This is very painful and has a low success rate (except for treating just the snoring issue – it has a high success rate for that). For severe sleep apnea, the success rate is nearly zero (which happened to me; I was mislead and told my chances of success would be 20 to 50%).
- Maxillomandibular advancement surgery. Details at this link:
This is extremely painful but has a fairly high success rate if (emphasize: IF) it has already been determined that Oral Appliance treatment is effective. But, this will modify your face. You will likely look like a different person (that could be good, bad or indifferent).
- Tracheotomy surgery. Although the success rate is effectively 100%, virtually everyone in the world agrees this is the treatment of last resort. You will have a hole in your neck for the rest of your life.
- There are numerous other treatment and surgical options (i.e. tongue manipulations). To mention each individually is probably beyond the scope of this forum. Eventually, a doctor with the appropriate sleep specialties needs to be involved.
If you want to reconsider ways to get your CPAP working for you, there are already hundreds of threads out there with all kinds of options and advice.