I looked into maybe getting a flipper a while back and decided the hackRF would be the way to go. I never got either, but from what I was reading, hackRF let's you do all the things people who own flippers wish the flipper did.
MAC addresses are assigned to the hardware and do not change with each boot (first 3 pairs are company second 3 pairs are the device), unless you spoof the address then you can make it display any MAC address you wish but the MAC of the device never changes.
Advertised WiFi MAC is randomized per AP by most devices these days, and Bluetooth also have equivalent privacy protocols. So unless you can get the device to connect to you then you won't see a static identifier that can be followed