Yeah, I don’t have good answers for you… I honestly don’t know what the best way to get people into it is. The resources really are not great.
FWIW I think when it does end up clicking everything is a LOT less complicated than it seems at first. Nix is sort of all about building up these attribute sets and then once that really sinks in everything starts to make a lot more sense and you start to realize that there aren’t that many moving parts and there isn’t much magic going on… but getting there is tricky. A lot of people recommend the nix pills, and honestly I think it’s the best way to understand nix itself. If you do earnestly read through them I think there is a good chance you will come out enlightened… they just start so slow and so boringly that it’s tempting to skip ahead and then you’re doomed. They also have a bit of a bad habit of introducing simple examples that don’t work at first which can be confusing, and eventually some of the later stuff seems like “ugh, I thought we already solved this” but it’s building up nicer abstractions. The nix pills give a pretty good overview of best practices in that sense, I think… so maybe it’s the source of truth you’re looking for (or part of it anyway). I think the nix pills are a bit more “how the sausage is made” than is necessary to use nix, but it’s probably the best way to understand what all of these weird mkDerivation functions you keep seeing are actually doing, and having an understanding of the internals of nix makes it a lot easier to understand what’s going on.