i'll have to recommend "practical doomsday" here - https://lcamtuf.coredump.cx/prep/ (edit: because it spends a lot of time on the topic on how to secure your wealth). or ask lcamtuf himself.
Off topic. It seems to me that "preping" became less popular after covid. Perhaps, people realized how ineffective it was when we encountered a doomsday scenario in real life?