You have the right idea by swapping out the one axis. Don't stop there. Plug the Z axis cable into the Y motor. This will tell you if the stepper driver on the z axis is wonky. I'm not familiar with the board for the Ender 3, but if the steppers are individually removable, you can do some swapping there too. Important, perform all swaps with power disconnected. If the steppers are removable, double and triple check that the pins are properly inserted. I've mis-aligned one stepper and let all the smoke out of the main board.