Does disabling the liftgate in the menu actually do much? On my 2017 disabling the power lift gate in the menu on the left of the dash has minimal impact on the power lift gate. It disable like one button. Could still open it with the FOB, dash button, handsfree...
In the manual, it does appear that there is a single fuse that is solely for the power lift gate which may be a way to disable. I've had issues with the liftgate auto opening and closing when I am working near the back of the car, putting stuff in, taking stuff out, adjusting bike rack etc. Also, opening the lift gate with the bike rack on, causes it to hit the bike rack.