Would love to find out if you find the culprit or what your fix turns out to be, I have a similar situation, 2017 raptor with 17” methods and stock KO2 tires with excellent ride quality, I went to swap out the center caps on the methods with flush method brand center caps and my ride quality went down the toilet, had the tires rotated and balanced, minimal improvement, swapped back to old center caps, no change, feels like the balance is way off, gets worse the faster you go I still have plenty of tread life left in the tires,
I’ve tired changing pressures from the stock 38 psi all the way around to 36, to 38/36, nothing helps,