Just replaced the lower steering shaft in my TJ. 180k miles, TJ with 2.5" lift. My suggestion would be to lay your phone under your car and take a video while you turn the wheels left and right. If you have somebody else to turn your wheel for you this will help massively, as you can just get under and look while they jiggle the wheel.
Chances are it's either your steering box or your lower steering shaft. Look for any shafts turning with play on the other end of the joints. There is normally a small amount of play in the steering box (about 5º) but not too much that it's extremely noticeable. Lower steering shafts are much more likely to be the issue as they're very exposed to the elements and have a large amount of torque on them while steering.
My lower steering shaft made the play in my steering wheel go from about 20º to 5º, so large improvement, as well as helping with bump steer and vibrations slightly.
