Who told you you have "moderate to severe" apnea? Not really overweight and only occasionally snores doesn't sound too severe to me. But what do I know?...though I question the "Sleep Centers" out to make a buck.

Here's a good book, check all the reviews and summaries:
Why We Sleep by Matthew Walker, PhD. A summary of the main ideas: https://www.memosmine.com/the-mine/...hew-walker-phd/