Replaced a ball joint (wow! not fun! first tried a pickle fork - no; then a puller - no luck; finally a $30 ball joint separator got the job done). So made one mistake at the end - torqued the nuts while the car was still jacked up. Was afraid to back them off and re-torque on the ground - thought I might ruin the one way nuts. So I'm wondering if that is why my steering wheel is a little mis-aligned now. I knew you need to have your front end aligned after doing tie rod ends - that's pretty obvious, but I didn't think a ball joint would change my steering wheel. It doesn't pull to one side or another, it's just not straight. Any insights would be appreciated.

If your alignment was good before changing the ball joint, and you only changed one ball joint, you can figure out which way the steering wheel needs to go and adjust the tie rod end on the side where you did the ball joint to try to bring it back to the way it was. This advice is void if you did both sides, but I have used it often when doing just one.

After I replaced a ball joint I noticed my steering wheel was a little askew, maybe one or two degrees. I attributed it to perhaps a slight difference in height between the original and the aftermarket part. It never bothered me enough to adjust the tierods.
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1992 745, >500k km (now gone, but not forgotten)

For me - anytime anything comes apart in the front end, it's possible that things don't go back in exactly the same place they were before. Also possible that the geometry of the replacement part (who knows who makes them now...) is slightly different. So the SOP (again, for me) is to check the alignment afterward. Your steering wheel not being centered when the car is going straight ahead is a sign that something moved/changed. Likely a simple matter of resetting the toe.

Not difficult to do in the garage yourself with 2 jackstands, some black thread and some careful measuring. If you're interested - youtube the process (easier than me explaining). Using the angle finder on my phone and a parallel string, I've done my last three alignments in the garage myself.