Even if you get local LEO’s to engage in kick down the door raids eventually through attrition there are more of us than them. You are correct. If the goons kill one gun owner and he/she takes out one or two goons the numbers quickly turn into a nightmare for the peddlers of tyranny.
I think the scenario is much easier for the Feds than anything describe here. After the SC overturns the 2nd Amendment, and then when it’s time to sign up for, example, Social Security and Medicare you will be asked to certify that you do not possess firearms as a condition for recieving these Federal benefits (and this compliance check would be enforced for all Federal programs).
You can lie if you wish. But the first time you are caught it’s the end of your benefits. There will be no massive confiscation because the goal is not to seize weapons but to silence the owners of the weapons.
Look around you. How many people do you know, are related to, go to church with, and etc that owe their monthly income to a government issued check?