Try researching rural vs urban, most of this crime happens in urban areas, Houston, Dallas etc. Texas rural rates of crime are significantly less than Texas urban and the US overall.
If guns and capital punishment reduces crime, it doesn't matter whether the crime happens in rural or urban areas. If it works, Texas, the whole damned state, should have remarkably low crime, but that's not the case at all.
You're having a different conversation than the one I'm having.