Germanic/Celtic tribes successfully used guerilla tactics to defeat superior numbers of Roman soldiers, and ultimately hamstring the Empire.
I disagree with your talking point about the common motivation of all democrats to disarm law-abiding Americans. Rather, the goal is to reduce the carnage of mass shootings, firearm suicides, juvenile gun deaths, etc. Our government has so far been unsuccessful, as proven by the #s. Other governments have been far more successful at this, and a large part of their interventions have centered around reducing the availability of guns in general to at-risk populations (children, mentally ill) and automatic/semi/high capacity firearms (Australia). Nothing else has been proven to work at reducing the impacts on gun violence on national populations. Obviously, proven solutions are preferred when other solutions have failed, particularly while the US body count exceeds 38,000 annually (2018).
I agree that absolute rejection of gun legislation tilts the political and public see-saw against NRA, etc. If the law of the land distills down to the right to life, liberty and the pursuit of happiness vs the right to keep and bear arms, 2A will necessarily lose.
I agree that lack of enforcement of existing laws undermines the effectiveness of existing gun laws on its surface. Sheriffs that refuse to enforce gun laws are a prime example, and a flashing neon irony. Some existing gun laws should be better enforced, some improved, some reconsidered.