Note that correcting an underbite by extracting/retracting teeth will likely make sleep apnea worse. Make sure you consult an airway focused orthodontist, not just any orthodontist, as many are unaware of these issues.
Now I'm not sure if its an underbite or an overbite that causes the issue, but I do know it's something that can be objectively measured and fixed. You're right though that I went to a specialist in apnoe to have my teeth/jaw measured.