Stripped threads on upper control arm ball joint socket

never had any threads to start with,
and the balljoint only has the mearest hint to get it to work its way in

Don't worry just start new joint in with arm in vice, use a rubber mallet to tap it down to the start of the thread. Once started and straight
fit arm to car to finish the job with a big bar.
if you end up not thinking enough effort was used to get it in you can wind it out and get a different arm...BUT its usually exceedingly hard work....

wind it in till the top section, the head of the joint, hits the pressed section in the arm you don't need to go much further you will be at torque spec, you are not doing a NUT up tight in the normal sense, you know what tight feels like and it should have been tight from the get-go, shallow thread in balljoint is cutting new ridges into the pressed arm...thats near tight enough with one last nip up at the end
the thread is for installation, its not there to be under tension like the thread on a head stud is , the joint is basically held in by the friction between arm and balljoint case. Torque setting in book was to stop "strong men" at the local alignment place from ruining arms

job done.

if its loose and takes no effort you have a problem, somone has over tightend the previous joint, or put it in very crooked . if its not loose for any of its journey IN, it aint going anywhere.
The balljoint would have to seize solid to wind it out
or the upper ARM would need to jam to punch it out
both in standard working form, move easily in comparison to the force necessary to knock out the top joint.

other option is to use a cone or socket in a press to gently reform/close up slightly the pressed section of the arm. go too far and you can't get the joint in.

make sure you replace both lower and upper bump stop rubbers to avoid binding joints at full travel in either direction and do up all "Bushing Bolts " at ride height with the car on its wheels.... at rest, all bushings includeing steering idler should be in relaxed not twisted position.

PS sure you need to change them.....? its the bottom joints that take a battering

Dave