QUESTION FOR UCA BALL JOINT SEPARATION

OK wait!
If you are not planning to replace that upper BJ, then there is no reason to remove it, nor to separate it from the knuckle. Removing the BJ is a lot of unnecessary wear on the screw threads. And reinstalling it is a bit of a trick, and if you get it cross-threaded (easy to do), then you may be shopping for a replacement arm. You can easily measure the wear on that part prior to removal. But if you are just gonna remove the stud to facilitate bushing replacement, that I can understand.But then, of course, you cannot beat on the threaded pin.
If I was in your shoes, I would remove the brake system, unbolt the lower BJ and be left holding the assembled UCA and knuckle and there you have it. That can be worked with.