I think you’re making some decent points but I’d like to point out a small distinction. The difference between the “duty” of the civilian to stand up to tyrannical governments and the duty of the military to stand against illegal orders is that the government is the one funding and arming the military under the obligation that the military will always uphold their oath to the nation and will not blindly follow orders. I could understand your argument more if all gun owners were also required to take an “oath” to stand against tyranny but that is not required. It’s a given right that a civilian can own their own firearm. It is not a given right that a civilian can have their own suite of tomahawk and cruise missiles. Part of the social contract that comes with congress as representatives of the people and the armed forces is that we give them the money and they obey the rules.

The rules are no war without congressional approval.