When I talk, I hear an click/crackling sound in my ear, mostly on 1 side. Hard consonants like k & p make it worse. What to do? It's debilitating.

Get help... Find a TMJ specialist. Most dentists can refer one to you.
Jaw vs eustachian . This is either your jaw joint or eustachian tube making noise. Sounds more eustachian by your description. It is benign but annoying as you note. If it is really bothersome one can try nasal sprays / decongestants / antihistamines.