Sounds like you need more positive caster to improve on center feel and straight line tracking.

I had alignment problems brand new. I had to get it re-aligned twice before they got it right.

First time they did the alignment at 1000 miles, they only adjusted the toe which didn't really help.

The 2nd time, the dealer had a more experienced tech redo it. He knew exactly what the problem was and added more positive caster (3.2°). Now it steers and tracks perfectly. I can take it to triple digit speeds (mentioned in another thread but got serious backlash ) and still feels stable.

I don't think some techs know how to a proper alignment. As long as the numbers are green they send you on your way.

Keep in mind, the new vehicle warranty only covers alignments for the 1st year or 12k miles. You need to get it done correctly pretty quickly before it runs out, otherwise you will have to pay for it.