One way to approach answering this question is looking at history. Do individual people with a nice stockpile and contemporary weapons tend to survive the collapse of their civilizations (or even local, short-term famines for that matter)? I don't think so. For example, in Europe the social/physical structures that successfully faced these situations were walled cities & towns. Castles. Entire communities and decades of planning and construction.

IMO, no way this scales down to a single household - I'm chuckling right now picturing a knight and their family in a house-sized castle.

Another angle: if things get bad even just food wise, people who have nothing to lose will keep coming - starving people who will die unless they get to your resources.

To me prepping to survive by yourself is a dumb fantasy and a waste of resources that would be much better spent building resilient communities.