Same here. Brand new AirPods Pro 2 with the USB-C case. They pair fine, noise cancelling is great, but nothing will make them show up in Find My. I've tried all the tips in the previous discussions on the topic (unpairing, only re-pairing as they're plugged into my MacBook Pro via USB-C cable, etc.) Nada. Several posts in the other threads say it is a hardware issue and you must return them and get another set. I'll keep trying for another day but will send them back to Amazon if I have to, unless someone else has an idea how to get them working.
EDIT: Here is a weirdness. I forgot them from the Bluetooth settings again and re-added them to my MacBook Pro. This time their name showed up with "- FindMy" added to the end of the name I'd previously given them. I did not do this. To me, this strongly implies that Apple's systems are trying to add them to FindMy and are failing. But I'm not sure what to do with this information. Can anyone from Apple comment?
EDIT 2: At this point the devices think the APP2 are registered with Find My. It's just Apple's servers that do not think so and are not sending the location back to the Find My app. Best I can guess is the servers reject certain device ID's and that's why you have to replace them and get an ID the servers will accept.