There's devices that don't have a name but use Bluetooth, low level. They show up as a mac address only. Tile, sensors, maybe air tags, they are only visible with a name in their apps. I have sensors in my camper that show up like that. Level and temperature sensors. I'm a bit skeptical but as always have an open mind. I would screenshot the mac address and look it up with a simple Google search, make sure it's actually a person. Even electric meters now do this I'm pretty sure.