Thanks for your reply. With regards to that, I've gotten the car inspected multiple times. First I was suggested to replace the brake pads which I did bcz it was due anyway. Problem was still there. Then complete wheel inspection and servicing was done which included the steps you suggested. Discs were completely smooth. No waves. Still light sanding was done + rear drums were also thoroughly cleaned. Problem was still there.
Regardless, if issue was related to brakes it wouldn't happen without braking (i.e. just lifting foot off the accelerator) but it does.
Moreover, I drive 80+ KMs daily and the noise happens on each deceleration in the morning for first 20+ KMs then usually goes away. Also, it is less pronounced in the afternoon on my return joirney when it only happens for the first 5-10 KMs. Noise without braking (with just lifting the foot off the accelerator) usually only happens when the AC is on. So it's quite random. Bearing noise is pretty much continuous (faced that in the past. Bearing was replaced. Hasn't bothered me since)
Could it possibly be linked to the eco idle system because it gets charged on every deceleration regardless of brake usage?