No different than if one child messes up the Lego build that another built. This is nothing new, only digital. Typical sibling annoyance.

Struggling to parent this issue is just showing signs of being a shitty parent.

You tell them to knock it off and teach one child to have empathy and care for others by thinking of how they’d feel if someone messed up something they built.

Sometimes you could also just chalk it up to kids being kids, so long as it isn’t constant.