While I don't experience ear popping as a migraine symptom, I have experienced ear popping after a magnesium float that I also thought was an ear infection, and I am very sensitive to air pressure changes.
The ear popping after the float was helped best by rinsing my ear with a saline spray: https://www.amazon.com/NeilMed-Clearcanal-Removal-Complete-ounce/dp/B005ZQ8HPE?th=1
BTW, the magnesium floats can help reduce my pain by up to 4 pain levels. Definitely worth looking into if you haven't tried it yet.
What helps me the most with air pressure sensitivity is MigraineX earplugs: https://www.migrainex.net/ The child size fits me best. I seem to have smaller ears than the average adult. I have bought the adult size, then three of the child size. I keep one by my bed, on in my purse, and a spare in case I lose one in my sleep. I have also bought a pair for my sister.
Hope this helps. I know a lot of times finding a relief is trial and error and what helps one person doesn't help the next. Good luck and hang in there!