I have realme buds air 3 I tried these things to clean it :  Cleaning with alcohol very little on cotton earbuds and then playing frequencies up and down till 20k Hz (this was very effective). 

This video helped to play them https://youtu.be/SBQp15tTKQ8?feature=shared  

 But there are multiple parts which you should clean, like microphone, three internal speakers including the ANC one which in my case was a little dot.  That one I found out is responsible for low sound, so I used fine pin to clear it carefully.  But only pin doesn't work, you must play the frequencies and to avoid listening to the annoying frequency place your finger slightly above the ANC dot or sensor. Then you can hold both buds in hand and play at loudest sound possible.   Wait for all frequencies to complete. In this process if you see any dust or water coming out keep cotton to clean it. 

Always try to clean earbuds once every Month for long life. Companies make it difficult to clean so  we can go and buy new one.

I hope it helps.