I feel that shift would be a mistake and be conflating things that are not related. Teen suicide rates have to do with teens feeling terrible about life and killing themselves. The gun is just the messenger in this case. A belt and a tall closet works too.

I have lived in parts of the country where there are extremely high rates of gun ownership and 0 problems with gun shootings. Then there are areas with much less gun ownership and very high shooting rates. Those areas, to be blunt, are generally low-income PoC neighborhoods. The leadership at the country/state/city level won't admit they don't give a shit about poor brown people. They want to blame the troubles of the neighborhoods on firearms and take those away.

I have a theory that mass shootings are a similar situation, that there is a shift in the mental health of people that is causing them to want to go kill a bunch of people just to kill a bunch of people. It's currently fashionable in certain (typically) young white disillusioned male communities to go buy a gun and go kill a bunch of people. If there were no guns, would that problem disappear? Or would they just use the kinetic energy of 4000 lbs traveling at 25-60 mph to accomplish the same thing, like in Paris? I don't know.