Your links are total bollocks as they refer to studies made on adolescents and teenagers, not actual kids which this whole thread is about.
I just googled around and found lots concerning children and violent games, movies, media and the effect they can have on kids.
Everyone doesn’t get affected the same way, but the risk of having kids getting affected by things at the wrong age should be avoided, therefore following information on game packages and the recommended age for certain games.
https://www.health.harvard.edu/newsletter_article/violent-video-games-and-young-people.

