Maybe the filters are dirty because of dust, earwax or it is moist because of sweat or general moisture in the your room or your place. Mostly, the filters are the main culprit for channel imbalance but can’t really say because I don’t have your unit!
I had MoonDrop Chu II’s and the left one was more louder than the right one. Changing filters was not an option since they were out of stock so after searching the web for a long time. I found that people were sucking on the IEM’s and that was working somehow. But those are IEM’s so can’t say for sure if it will work on them NEARS.
I don’t know if it works on Earbuds so don’t try this and contact Nothing Support Team!
For the time being, adjust the audio balance from audio adjustments in Accessibility settings on your phone!
Have a good day!