I'm just adding an advice, I don't know if it's mentioned since I haven't read all post, but here it goes;
Try vaping nettles. I saw someone mentioning it working as an allergy medicine so I had to try it, and it really works (for me at least).
Your not mentioning allergies as one of your problems, but the reason I mention nettles is because when I vape it it doesn't just stop the allergy, but it loosens up the mucus and seems so slow down the constant production of it.
It doesn't taste good, but it weirdly effective, for me at least
Nettles = Instant allergy medicine
(And hopefully an instant mucus remover in general)
Best of luck!