How do you organise multiple git repositories, so that all of them are backed up together?

I would strongly advise against putting unrelated data in a given Git repository. The overhead of creating new repositories is quite low, and that is a feature that makes it possible to keep different lineages completely separate.

I want to add to Damien's answer where he recommends.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.