Possibilty to suppress automatic screenshot upload?

The iOS app work’s well on my kids and my wifes iPhones. But my son is driving me insane with screenshots. He plays a game and during that he makes a lot of screenshot e.g. to build collages or share with his friends by instant messenger.

Unfortunately these screenshots are a couple of minutes later all in the nextcloud via automatic upload. On the Android App I can easily suppress that, but I can’t find a similar option in the iOS App. Am I to stupid to find that or is that impossible with the iOS App?