I'm curious to hear your explanation for Switzerland. Approximately 25% of their populace own guns yet their gun violence rate is nearly immeasurable.
Firstly their level of gun ownership is so high largely due to the fact that military service is mandatory and they are able to apply to buy their weapon afterward. So not only are a large portion of those gun owners active military/police but almost all the rest are ex military and have received appropriate training.
Secondly, within living memory in fact, they have had a strong need for a well armed and trained population due to being bordered by potentially hostile powers. And now that that danger is being relegated to history they are actually reducing the number of guns.
Thirdly, they actually have quite strict requirements for gun ownership and permits for owning them are usually issued at a local level and can involve more details background checks and psychological assessments.
TLDR: Almost all gun owners are active or ex-military/police with extensive training. They needed an armed population for national defence, the right to own a gun is still heavily restricted. None of which are applicable in the US, therefore Switzerland is not evidence for less gun control, it's actually more evidence for greater gun control.