Or, if you’re using only one or few distributions you can preseed the image and have the installer do the stuff for you.

That’s something along the lines I do as well, but your methods are far more in depth than mine. I just glance around documentations, how active the development is and get a rough idea if the thing is just a single person hobby-project or something which has a bit more momentum.

And it of course also depends on if I’m looking for solutions just for myself or is it for others and spesifically if it’s work related. But full audits? No. There’s no way my lifetime would be enough to audit everything I use and even with infinite time I don’t have the skills to do that (which of course wouldn’t be an issue if I had infinite time, but I don’t see that happening).