If you wake up a lot at night and still feel tired in the morning... have you tried doing a sleep study? I believe that obstructive sleep apnea is severely under-diagnosed.
The newer Oura rings actually have an integrated pulse oximeter and can measure apnea, but mine does not.
I wonder if I should just buy a CPAP on my own and see if I feel better. I probably should also lower my bodyweight... I am a weight lifter, although fairly lean, I am a big guy, and losing some weight might reduce apnea events.
If that was me, I would pester either the same doctor or a new one to get a CPAP machine. It's not a set and forget device, you may need to try a few masks and tweak the settings until you find something that really works for you, but once it's dialed in it makes a big big difference to your quality of life.
Trying to lose weight when you are not getting adequate sleep is an uphill battle. There are plenty of lean people that still need CPAP to get adequate sleep -- I was one of them.
I have two other major health conditions that badly needed treatment, which Kaiser would not treat, and I paid an outside doctor with cash to be able to receive treatment.
Regarding buying your own and learning to program it, I had to do this anyway. My dr was not helpful after I received the machine, and this is true more often than not, which is why so many people don’t take to the treatment.
Look into OSCAR software.