The learning curve of NixOS is also what keeps me from trying it out, hence I prefer the “take it or leave it” mantra of the immutable fedoras, and try to keep the amount of packages I have rpm-ostree layer on top minimal.

As for Distrobox, yes there’s ways it can fail, altough that happened rarely to me. What happens mostly is that the distro inside distrobox goes kaput because that’s just what mutable distros beared with a plethora of questionable tooling installed with “curl something | bash” does. But for me that’s the point of distrobox: separate all that shady cruft one may need for work/developing/etc from the host os. It’s a place for messing about without messing up the computer and with it the bits that need to keep working