PW4 Bluetooth connection

I can easily enable Bluetooth and connect my "All New Paperwhite (10th Generation)" firmware 5.10.3 to

- My bluetooth headset
- My AM/FM radio + bluetooth input
- My car infotainment system

but never to
- My Android phones
- My iPad
- My PCs running Windows 7

Is that to be expected? Why?

I just wanted to trace the PW4 Bluetooth MAC address, once connected to a PC. Has anyone been more sucessful than me?