I always manually turn on/off whatever connection I (don't) need at that moment; bluetooth, wi-fi, cellular data
On iOS is it really ‘off’? Surely it’s on at some level in order to widen the network for AirTags?
In my experiments a few years back: Off in control center still transmits a static UUID every second and changes the UUID about every 12-24 hours. It only stopped "beaconing" after going into settings and turning bluetooth of there. I used hcitool -lescan on a pi to find this out.
I mean, even if Bluetooth was completely safe, I'd still turn it off when it's not needed to save battery.