I’m surprised as your tires are very close to the stock Z71/AT4 size. I’m running a 3/4” taller tire (315/70R17) with slightly less offset at stock ride height. I also have the power running boards. I only rub at entry / exit ride height (approximately 2” lower than normal).
Based on your description, I suspect you haven’t done anything to the wheel liner, and you’re rubbing the liner just above the running board. There is a bracket behind the liner, just above the running board, held in place by 4 bolts. Remove the bracket the tie the liner back to the frame. I used a self tapping screw into the small divot in the frame. Once done, it’s completely unnoticeable from outside and you would have to be quite familiar with a Tahoe/Yukon wheel liner to tell, even with the tire removed. Sorry but I don’t have any pictures of my mod. There were several good photos a few posts back showing behind the wheel liner and the Westcott Design YouTube channel has several videos on their fender liner kit. Strictly speaking the kit isn’t necessary but should make the mod even easier.