This doesn’t sound like your issue, but I had an AirPods Pro case which needed to be replaced after about 6 months. The left side stopped charging. I looked at the little electrodes at the bottom and they were not gold but looked so dark they were almost black. I think they were rusted out from me putting in my sweaty AirPods immediately after running on hot summer days.
Since they were still within the 12 month limited warranty, Apple replaced the charging case.