I have a 1999 with about 4.5" lift with RE springs, RK long arms, WJ knuckles and one-ton steering.
I only recently developed severe DW last week. Just like you, everything is "tight" and all parts are new given the wj swap was last year. However, my TB bracket on the frame side wallowed out some holes because I haven't gotten around to fabbing up a brace for it yet, and apparently finally got to the point where it allowed enough movement to start the chain reaction that is DW.
I think you've missed everyone's point here that you can have all the bolts tight to where they don't move, but once you get someone cranking the wheel, you will realize just how much things can move when tight.
Have you had someone jacking the wheel while you lay under and watch everything? Steering box? pitman arm? Draglink? tie rod? Trackbar at both frame side and axle side? Stabbing brakes and watching the control arm joints? Everything can be new as in my case, but wallowed out, and castor, camber, toe, can mask or unmask those things. In my case its probably a combo of the TB bracket moving, and a worn axle side control arm joint, and once I fix those, if its persistent I'll start checking the castor, and everything else.