Please tell us some basic information before asking for help:
Model Name: M1 pro
Firmware Version: 424
Rooted or not: No
Frequency of Occurrence:
APP Name & APP Version (If your issue relates to the app):
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
I think i get it why there is no bass in earphone. So i was playing COD, there is no such issue like no bass. Sound was crystal and clear with bass. Then I switched on my mic. And boom, bass gone. I think it's a mic bug; and not sound bug. Also if you don't want to downgrade but listen to songs on build 424 with bass, make a call before listening to songs. Try it.
Edit - I managed to play songs after closing COD, the bass is top notch. Better than 063.