By the way, I think my initial reply reads dismissive, but my intention was to try and make clear that whatever is happening isn't normal aging. Can you see a second doctor? Fatigue is such a vague symptom, with so many possible reasons, but what you're describing could indicate a lot of things and you need a doctor who will take it seriously.

My friend was able to do a mini sleep study from home recently, to test for sleep apnea. I noticed when we were traveling together that he sometimes gasped in his sleep, and he told his doctor about it. I think there are DIY sleep monitoring apps but I don't know if they're any good. Might be worth looking into, if your doctor isn't helping. Or find someone to listen to you sleep.

The range of possibilities with bad fatigue is just so big. I can only make suggestions based on my own life experience, but a doctor in your corner would be able to look for so many more things.

Oh, did you have a bad illness at some point before the fatigue? Covid isn't the only virus that can have confusing long term after effects.

A relative with fibromyalgia had constant farigue, but I think pain is a factor with that one.

I can keep thinking of possibilities, unfortunately.