Alcohol and surprisingly even 0% alcohol beer (not sure how much I can attribute to nocebo effect) completely wrecks my sleep. My nasal mucus thickens so much that I can't breathe properly when lying down. And it's not like I'm not drinking water and keeping hydration in check when I drink. I gave up on alcohol completely.

I confirm that exercises do help. Anecdotally last week I woke up with an obstructed nostril. I tried to fix it by washing it abundantly with saline solution, did it a dozen times without much success. Later I went to ride on my road bike and in less than 30s both nostrils were perfectly cleared.