Hey there, just thought I'd pop in and tell you what literally just happened for me that got mine to connect again (I was having exact same issue and had tried every logical fix up to page 3 on Google search). For context, I have an iPhone 11, and my connection issue started right after ios 15.2 update. So it occurred to me a minute ago that it would be more helpful to figure out if it was an issue on the phone's end, or the airpods, so I tried connecting them to my husband's android phone. Just to be safe, I left my phone in another room with the bluetooth turned off and did another reset on the airpods.
Then: (1) turned on Android bluetooth and put it in pairing mode. Waited a few seconds to make sure it was looking for devices.
(2) held the reset button on airpods until it started flashing white, and checked to see that the android was seeing the airpods
**maybe a one-off, but weirdly, they were showing up in the list with the name I had originally given them despite multiple resets, and his phone "couldn't communicate with them". So...
(3) Turned off android Bluetooth, did another airpod reset, and tried pairing them again.
(4) It worked! They showed up as just standard Airpod Pros and worked when tested O.O
(5) Did one more reset bc I'm paranoid, and then lo and behold, they connected to my phone for the first time in several months.
Not sure if any of this will help your specific situation, but I absolutely understand the frustration and thought I'd share just in case. I suspect that something was getting hung up in the communication between Apple devices, and that maybe having the airpods "try a different language" sort of snapped them out of it...whatever 'it' was. Good luck if you try this, hope it works for you!