What exactly do the different types of stage3 archive do?
I've heard that you should be using the appropriate stage3 archive for the profile you want to use, but what exactly are the differences between them? I'm asking this because I want to try doing a Hardened/SELinux/Musl/LLVM install, and there's a profile for that, but not the stage3 archive. I was thinking of starting with either Hardened/Musl or LLVM/Musl. Any thoughts on that?
From my understanding, it is okay if a stage3 archive does not exist for your target. Make sure to pick the closest one. Your approach seems right imo. I am not sure if hardened or LLVM is better though.
My understanding is that a stage3 is kind of a starting point. In many cases you can switch profiles, and all that will happen is it will just have to do more compilation to get there. Choosing the closest stage3 saves you time in that initial compile.
But some profile switches can cause trouble. For example, switching between glibc and musl may not work. But switching between, say, non-desktop to desktop is perfectly fine.