Just go to the Applications directory and delete BFD3.app and BFD License Manger.app.
The system level files are in /Library/Application Support/BFD Drums. The user level support is in User/Library/Application Support/BFD Drums/BFD3 and User/Library/Application Support/BFD License Manager. You can just blow those away, too. If you really want to double down, your temp keys are located in User/Library/Application Support/com.inmusicbrands/softwareunlock. Blow that away, too.
That’s complete removal of installed software. In general, not totally necessary, but not harmful, either. All your licenses exist on the inMusic server. Just make sure they’re there in your account. Or, in some email, or written on a sticky, so you can prove they once existed should you need them.
Otherwise, your user presets, grooves, and kits (which, I expect are the really hard to replace things), are all kept in Documents/BFD Drums/BFD3. If you want, you can just move BFD3 out of the way, and move all that content in piece-by-piece.
(And, if you’re skittish, just rename all these directories instead of actually deleting them)