You can't stop it, but only Samsung can do it. I think disabling galaxy store before software update might help. I don't know if it works or not but give it a try.
Noo this is not a way . After every update there is some page that appears for installing new applications . Many times is gets skipped ans the akready selected apps get installed . So after every update u need to see what all appears on ur phone. Of u think u have missed it then just go in notifications (if u have enabled notifications from Galaxy Store , if not then enable it ) and see is anything is installing and then click on it . It will take u to the page where it is downloading there u can stop it.
that's not true --- when opening galaxy store these options will come , But on phone updates - NO . Galaxy apps store is just the same as Google store - yet annoying with alot of notification so I keep it disabled anyway. if I could Uninstalled it , I would have....
