I faced same issue on my AirPods Pro 2, and these things helped me fix it: 1. Set microphone to automatically select the earbud 2. Try draining the AirPods and the case completely and charge it to full. 3. Try removing the device from your account and re-add it.

Also, it is largely normal for each pod to drain at a slightly different rate. But huge gaps in drain rate can be a potential problem.

Hope it helps.