The biggest issue is getting on to the top of the balljoint to pound it out - if you’re doing the front wheel bearing you’ll be pulling the driveshaft anyway, so you may be able to get a good swing on it that way.

I would recommend supporting the knuckle on blocks when you hit the balljoint - you will be really hitting that hard, and it’s not going to do the shock tower or other joints any favours if the load transfers to them. Also there’ll be a fair amount of movement without he control arm in place.

Personally, I think you’ll find it easier just to get the knuckle off completely and do it on the bench. If you’ve pulled the driveshaft and removed one control arm, it’s not a big deal to remove the other two and the two big bolts holding the knuckle to the shock tower.