Up to today there were more deadly victims in the US from the second amendment then Ukrainians that died in the war. The US took a big advantage the last few decades.
The root cause of gun violence is substance abuse related crimes. I recall a judge remarking that if there where no substance related crimes, they could close his court room. As far as school shootings are concerned, the odds are high the kid came from a broken home where substance abuse was often seen with the kid effectively being raised by the TV or often the least common denominators on social media.
Schools have been on the front line of mass shootings involving children, by children. It seems to me that as an educational institution, a school can have an impact on reducing such incidents. Tools available include specific curricula involving the issues of substance abuse, mental health, broken families, and school shootings. In addition, school faculty should be better trained at identifying and taking appropriate action involving at-risk children.
While I support children being trained in the use of firearms at an early age by a responsible adult, such as a parent, we need to review the chain of events that a dangerous child comes into possession of a firearm without effectively annulling the Second Amendment.
I believe implementing the above ideas as well as addressing excessive violence in the media will reduce, but not eliminate school shootings. In the end, if someone wants to kill people, they will find a way whether it involves guns, explosives, poison, a vehicle, or arson. Maintaining gun ownership rights for responsible adults and even certain children can help reduce risks of mass casualty events, whatever the cause.