Also a request for any resources of scientists trying to get their head around how to write good software, we're all pretty much people who once read a C++ tuto

Also a request for any resources of scientists trying to get their head around how to write good software, we're all pretty much people who once read a C++ tutorial and just went with it. That is an interesting question I had not thought of. I genuinely cannot think of a single resource that teaches good software engineering practices, like how to structure code in a robust and maintainable way. In fact, many books that I read usually include examples using terrible coding practices. And then the ones dedicated to software engineering are usually too out of date or academic (GoF, Fowler books). I would say read up on inversion of control and dependency injection. And then a book on unit testing. Writing your APIs to use dependency injection and making them easily testable (by testing output not internal state) gets you most of the way there.