My right AirPod is sufficiently louder than the left one and I don't understand why?

My right AirPod is sufficiently louder than the left one and I don't understand why.

I have tried going to audio/visual in settings and the slider is balanced, I have also cleaned them so it can be because they are dirty and following this I also reset my AirPods.

any help would be appreciated

[Re-Titled by Moderator]