Remapping 8bitdo zero2 controller to undo cards

I have been using an 8bitdo controller for the past month or so and it really makes anki more enjoyable compared to smashing keys all day. However, since I bought it I cannot find a way to may any of the keys on the controller to “Undo”. This action (cmd +z) cannot be mapped to my knowledge on karabiner elements thus I cannot change it on my controller. Is there some way I can change cmd+z (undo in review) on Anki desktop to lets say: left_command (a single button operation) that I can then use in karbiner elements?