Types of Magnets to use for Bluetooth and electronics circuits
A magnet produces a static magnetic field (or even if you moved it as fast as you could, an extremely steady one), so that doesn't interfere at all with radio waves.

You'd be getting into trouble if your magnet was so strong that it lead to nonlinear effects. But unless you plan to affix your bluetooth device using an MRI, I doubt you'll be able to measure these effects without a lot of research budget at all.