This may not be helpful, but since you asked for experiences:

I had allergies as a kid, so never could breathe through my nose easily, even as an adult when the allergies eased. Yoga unexpectedly fixed it. The breathing exercises in particular, at first nothing opened but over time my nasal passages opened, or healed, or whatever had to happen and I now breathe easily and comfortably through my nose.

So if the drugs aren’t working and it’s a nasal thing, no itchy eyes, etc. it’s worth trying yoga, and when gunky maybe the neti pot (boiled and cooled water, a little salt). I really had no idea yoga would have that effect so pretty sure it’s not some placebo thing.