One Airpod Pro is quieter

After more than 1 year using my Airpods Pro daily, my right Airpod Pro got quieter with no reason at all. It didn‘t drop on the ground and it was never in a wet area. I tried forgetting them in the settings, I tried changing the balance between the two Pods but nothing really changed because the right Airpod‘s sound has become duller. For example, if I listen to music then the voice is perfectly centered but the background instruments are louder on the left side. That‘s really annoying thus the 3D-Audio doesn‘t work as good as it used to before. I also cleaned them both but no, no ear wax to be seen. Can someone please help me because I can‘t seem to fix it myself.

Thank you