Uneven tire wear

[encorehunter]

I took my 2019 ram 3500 dually back to the shop today because of the front tires. I was told the pressure was too low which was causing the uneven wear, both front tires are at 65 psi, which he said should be at 80psi. It is on the outside of both front tires. The truck was aligned when the new tires were put on. These tires have 6000 miles on them. In 30k miles, this is my 4 th set on the front end. It has been aligned twice in those 30k miles. Is this normal for a dually and I?m just ignorant about them? The tires did not get rotated as they were already in bad shape at 5 k miles.

The firsttire is the passenger. Before the last alignment, the driver side wore to the cords first. Now the passenger side is to the cords. Do duallys usually wear tires this fast and or uneven? The dealership said it is normal wear. The shop says it is from low pressure.