My AirPods were doing the same thing and the squeaky noise was so annoying. It was ear piercing. I was so sad because I have had them for only 5 months. I did all the troubleshooting including restarting to factory settings, everything but nothing like that worked. Until I figured out what the problem was. They were just dirty. I had taken them to the beach and there were two grains of sand in the right one. I took the rubber attachment off, rinsed it with lukewarm water making sure the water didn’t get inside (holding the pod upside down) and dry with microfiber cloth that won’t leave any residue. I also rinsed the rubber attachments. Problem solved! I’m so happy because I was planning a trip to my nearest Apple Store already and it’s not near me.
*I’m telling you what I did, I was very careful with the water. If you happen to do it, please do NOT get water inside it. Do it at your own risk.