I see your points but your argument is all over the map. Let’s confine it to modern open democracies, where the facts are easily gotten. Iceland has less than 400,000 people total, that’s likely to skew just about everything, so Iceland’s out.
And the other examples you offered are equally questionable, Switzerland has a people’s army that requires all males and many females to own a long gun. On Venezuela, why bother throwing that unmeasurable mess of a nation into the mix, as for Cuba, they appear to be a quite safe place (read the non US press) and China, with a billion and a half answers to no one, and certainly gives out no statistics to be measured.
Try the UK, Germany, France, Canada, Italy, Australia and many others. There you’ll find that not only do they rate far below the US in gun crime, they are on watch that the American model is strenuously avoided. After local mass shootings Australia, the UK, Canada, Germany and others tightened up gun ownership by quite a bit. Their social scientists and simple common sense saw that ‘more guns, more shootings’ is obvious.
In the States after some terrible shootings the NRA, and a large segment of the Republican party, offered a few obscure and ambivalent quotes from some venerated Founder or other, then did nothing.