This thread has a similar issue and the steps given resolved the problem. Have a look and let us know: AirPods 3rd gen not updating firmware - Apple Community Cheers! Reply of 1 AirPods 3rd generation model no is A2564 Welcome to Apple Support Community A...
We want to help you resolve any issues you're experiencing with your AirPods but we're not sure what you're experiencing exactly. If you share some additional information on this issue, the community may be able to be more helpful in troubleshooting this with you. Feel free to reply back...