Just went through this madness because my left airpod pro started having distortion issues (long winded, but hmu if you want more info). Realized i never had actually done the ear fit test (med was perfect for me out the box, didn't know it even existed). I tried the test with every size, nothing worked, moved them around, etc... spent a good 45 minutes trying to no avail. Every size failed, no matter how much or little i played with them in my ears.
I talked it over with support, they said i could walk into an apple store, that they didn't have any way of setting reservations for AirPods. But they should be able to help me quickly. They are still under warranty.
Went by the store closest to me this morning, they checked and were willing to replace my left, but i had to drive to another apple store because they didn't have it on hand there. I drive over to the other store to get my new left airpod pro. It took a while updating and setting it up, but it instantly passed the test on the first try, while the right one continued not to pass... i asked them to replace the right one, of course it wasn't on hand at the store i was now at, but it WAS in stock at the apple store I had come from. I went back to the that store, was given a replacement right airpod pro.
At this point, what I had told my boss would probably take a half hour was already up to two hours. I went back to my office before updating and resetting. Half hour later, I connect, first test passes. I've got two new airpod pros working great, but there was a few hoops to get them. No charge, just a good chunk of my day and driving.
Oh... they DID charge me for replacement tips when i asked the support person via text. BUT i DID get some free ones with the new AirPods. So, YMMV on that front.