MacBook Pro 2015 Big Sur bluetooth not working

Hi,

I have macbook pro 2015 (15'') and upgraded to latest OS Big Sur.

Today, I tried to connect/pair my brand new Sony SRS XB-12 but laptop did not find the speaker.

The speaker pairs and works fine with my android phone.

In fact, it seems laptop bluetooth doesn't find any device.

I have tried laptop to find another Sony headphone and a boss soundlink but nothing seems to be liked by this laptop.

I have tried several suggestion

1. Turning Bluetooth on/off

2. Switching speaker on/off

3. Deleting bluetooth plist files

4. Booting laptop in safe mode

5. Resetting Bluetooth module, removing all devices by pressing option+shfit

6. Resetting SMC

And everything above in various combinations.

In all these tries, I could see my speaker was detected by laptop only once but it failed connect.

I restarted the laptop and speaker and again laptop didn't detect.

I have wasted whole day, it's very frustrating.

Any help/suggestion is appreciated.

Thankyou