I'm not sure you actually have a problem....
The "popping up" thing is normal I think. Those nuts Never needs to be tightened though. That's not how it works, it's a taper that, once tight, doesn't loosen with wear. That wear happens inside the joint not where it attaches to anything.
So, get someone to wiggle the play, back & fourth, in the wheel while you're underneath. Does that joint have slop in it? If so, it needs to be replaced (and once you remove that castle nut, you'll appreciate how "locked" it really is
Do you have too much slop in the system? If so, look at all the joints as that play is being wiggled. Find where the "unproductive" movement is occurring but, remember, there's actually supposed
to be a little slop, mostly from the steering box itself.