I agree cupping could be tires. I changed my fronts (stock size 19.5 225) from Hankook DH01s to Bridgestone M724Fs and no more cupping even though I’ve used the Bridgestones longer. No alignment or additional shock changes either.
BTW, the Bridgestones are also all position whereas the Hankooks were drive tires. My SRW also cupped the Hankook DH01s in 245 size. Not a huge problem since I still had 40K on them when I traded, but I switched to the Bridgestones because we were doing a lot more highway driving. I just saved the Hankooks for spares that I took off the F450.