Yea, the 25 age would never be ruled constitutional, but it would be effective. Before everyone spent their time behind screens, we used to go out to clubs, drink and hang out as young men. We went places and did activities with our peers. That is also what seems to be missing from many young men as they brew their hatred of others in isolation or with toxic crap on the internet.
Remember the anti smoking public education campaigns years ago. I think they were largely successful in changing public behavior. I would support something like that with guns. Of course the gun lobby would stop it but I can dream….
Personally, I think far too many people buy guns without fully understanding and accepting the supreme responsibility that is assumed with that purchase. The gun is sitting in the house, waiting forever to do its job. People buy it, practice with it a bit, forget about it, get tired of it, maybe their feeling of being in danger is gone, maybe their mental health status changes, maybe their kid now becomes a young distraught man, maybe they just get old and die and the gun still sits there, waiting to be used. Guns last longer than the people who purchase them, thus they are everywhere. Safe storage laws, prosecutions of negligent parents, PR persuasion campaigns to turn them in or discourage their purchase, liability insurance requirements (probably unconstitutional, but I think would be effective). It’s a wicked problem and one without easy answers but to do nothing is also not an answer.