The reason tires tear up the tailgates is due to tires no longer being properly secured from behind with the rubber bumpers that are bolted to the tailgate. You need those to be secure to the back of the tire to keep it from moving. Otherwise any tire, even a stock tire, will destroy the tailgate. This is why the factory uses the bumpers.
Aftermarket wheels will relocate the centerline of the wheel/tire outwards, making a gap between tire and the bumpers. The bumpers can be extended, but ideally a more stock wheel should be used to keep the wheel closer to the tailgate in general, to keep the weight not so far out.
A bumper mounted tire carrier can work to solve the problem, although those have their own downsides.