I'm sure you've tried everything under the sun, but if you haven't tried it, see if Nasalcrom does anything for you. A doctor recommended it to me when I had COVID, and it was the only thing that cleared up my nasal congestion. It's inexpensive but hard to find, but it's available on Amazon.

You definitely know more about your allergies than I do, so I apologize if unrequested advice annoys you--it's certainly not my intention.

I'm sorry that your allergies are so bad. It sounds miserable :(