I've never yet known one that works via bluetooth? (Toys, possibly).
Bluetooth links add a slight delay to the audio, which generally makes it unsuitable for real-time / live audio.
A lot are wireless, but use dedicated FM or digital links. Many others are just conventional wired hand mics.
If they were bluetooth, that is a frequency-agile system; it coexists with WiFi an many other things in the 2.4 GHz band; it would be pretty much the last service affected by any kind of "jamming" device.
[Plus deliberate interference is criminal, in most countries].