So I Had to Send My AirPods in For Repair.
The left bud was hissing whenever I had it on noise canceling or transparency, so after a 15 minute chat with an online Apple "Have you tried resetting them?" representative, said rep agreed that even though they were out of warranty, repairs were covered under some extended program and they needed to be sent in.
I was a little hesitant because I didn't want to be without them for however long it was going to take, and quite frankly I wondered if I could just live with the situation until the AirPods Pro 2 came out in a few months which we all know I'll be grabbing up the moment they're available.
When the postage-paid return box arrived two days later however, I threw any misgivings I had to the wind, packed them up and sent them on their way.
I got a the next day that "Mark's AirPods Pro have been left behind." I'd completely forgotten I had that enabled, but also thought the feature was supposed to work in a much more timely fashion. But whatever.
I clicked their location in the Find My app.
They were already at the repair facility in California.
The next day I got an email informing me that they had been repaired and had been shipped out.
I checked the location again, and they were still at the same facility.
The following day I got notice that they'd been delivered to our PO Box, so I checked the location again.
It turns out they just replaced both buds outright; the old ones were in California waiting for their ultimate disposition.
Apple replaced my Airpods Pro for the same hissing sound issue, and like yours they just replaced them outright. Glad they did, because it was driving me nuts! But those suckers saved my marriage in the first few months of the pandemic, as they allowed me to ignore my husband's meetings on the other side of our tiny apartment.