Plan B was to treat it temporary like it is, avoid lifestyle inflation, save and invest such that you won't be impacted when the job market comes back to earth.
There will always be jobs in tech, but what will change is how well paid they are and how enjoyable they are. If you're not dependent on it for survival then those two things matter less, and you can even look to career switch into something more "normally paid" if the enjoyment factor starts to weigh on you. I don't get the family & friends part with layoffs - your concern should be you and your dependents (a subset of family).
Not sure why you're lumping in layoffs with wars here, the two are very different scenarios. I don't think you can really plan for war in any meaningful way except for ensuring your financial, mental and physical health is as good as it can be. Preppers are probably just trying to sell you something.