One thing I noticed when I started flying was that my ears stopped popping
after about 20 hours.

Benefits of a big head, I guess. ;-)

No, benefit of clear eustachian tubes.

If you go up to 10 K next time you have a head cold, you'll discover
you are NOT "acclimated." DON'T DO IT. It's excruciatingly painful.

Even during WW II, air crews were grounded for the "common cold."

vince norris