I have dust mite allergy and had infection-prone sinuses for years and lived with a chronic feverish feeling. I recently had FESS, using endoscope blades to clear passages. I slept great for a few weeks and then allergic symptoms came back again giving me muscle aches and a racing heart. So I wake up unrested. My Huawei band says I get recommended amount of deep sleep but deep sleep continuity is lower than recommended. I am waiting for the dust mite SLIT vaccine to kick in, it could take a year more. Till then I'm trying to isolate the mites in bed.
I had this exact issue and had a septoplasty procedure 4 years ago to fix it. The results were truly life changing because I could breath without being congested from dust mites. I had no idea how bad it was until I could breathe after the procedure. I can recommend my ENT specialist if you are interested. Getting this procedure cleared my nasal passages permanently and was probably THE best decision of my life. I can focus now.
Then fly to Palo Alto and get the procedure done. It costs $5K. The recovery time with Dr. Li is quick. I went back to work 2 days after the procedure. If you are suffering from lack of oxygen during sleep, you are living in a fog. Do whatever you have to do to fix it. Good luck!