UPDATE(20th Feb 2021) on my issue:
Prior to updating to Big Sur 11.2.1, I had tried the following steps:
1.) Clean re-install macOS, including re partitioning (i.e. from scratch!!!)
2.) Reinstall the macOS that came with the laptop(Catalina) - I didn't face this issue here.
3.) Tried NVRAM, SMC reset, almost a dozen times!!!
Only to find that the problem "still persists!!!",
Happens to whatever media that I play!!!- Spotify, Apple Music, YouTube on Safari
What am I missing here?
What additional steps can I take?
Have already contacted Apple Support, even they were surprised to see this erratic behavior!