Chronic Post Nasal Drip

Hello; I am a 46 yo male. I have had Eustachian tube since age two. 40+ typanostomy placements bilaterally. 4 cholesteatomas remove with tympanoplasty, twice each side. One year ago I started experiencing post nasal drip. It led to bronchitis and then pneumonia. My ENT sent me to their allergist, I was mildly allergic to grass. Started two nasal sprays, a steroid and an antihistamine. There was no improvement. ENT did a CT of my sinuses found blockage and performed a septoplasty, and opened my turbinites. Surgery did wonders for my breathing; however the post nasal drip is still happening. I am constantly sniffing stuff at the back of my throat/nose into my throat. It is incredibly thick (consistency of rubber cement) which then gets into my upper airway causing me to constantly clear my throat. The only relief I get is if I lay my head over the edge of the bed, fill my nose with saline for 5 minutes then blow my nose and repeat. This alleviates the symptoms for 10 or 15 minutes. The water that is discharged from my nose is clear, however if you reach your hand in the bowl you can grab a handful of clear mucus. It bad enough that if I am not constantly nibbling on something I get sick to my stomach. It annoys everyone around me as expected. It also gets better at night when I am laying down. I use a CPAP and I don’t wake up feeling like I have PND; however within 5 minutes of standing up It starts up. I have a humidifier in my room as that was a suggestion. Has anyone else experienced this?

Thank you in advance