The wobble your having is your brake rotors. All makes of heavy duty trucks have the same issue after getting on the brakes hard for an animal crossing the road or holding the brakes to long with a load on, basically overheating. I put a set of slotted and drilled rotors and matching brakes in the front and it all went away and never came back. Some people do all 4 but I’ve had two trucks that I only did the front and they’ve been fine. When it comes to the steering being stiff, I’ve had it on both trucks. Boys at the shop looked at it and said everything is more than tight, but the lube shop missed a couple grease nipples and that helped a lot for about 15k. If I wash the whole underside of the front steering components and brakes, it also goes away for awhile. Can’t pin point that issue just yet