Can I change the functions of buttons and knobs to suit my preference?

Yes. You can do this when the XDJ-XZ is connected to rekordbox Performance mode or Serato DJ Pro.

■rekordbox
rekordbox has a MIDI Learn feature. You can use it to change the buttons or knobs that features are assigned to. For details, see the MIDI Learn Operation Guide [here].

■Serato DJ Pro
Serato DJ Pro has a Remapping feature. You can use it to change the buttons or knobs that features are assigned to. For details, see the Serato DJ Pro Manual on the Serato website [here].