It could use shell scripts, custom programs, or whatever. What's the best experience and tooling you've ever seen?
Because there isn't a stable system interface table in Linux (i.e. INT 21, AH=9 prints a $ delimited string in MS-DOS, and has since the 1980s), you can't just run an executable.
The closest you're likely to get is Justine's APE - Actually Portable Executable[1] to get something you can distribute and just run.
Outside of that, NetBSD. Download install kernel, write to media, boot, compile an entire system.
FreeBSD is also good.
Pet peeve: I see lots of system projects that look very cool but only boot from qemu.
Another one would be Nala, I used this as my day-to-day apt frontend before I switched to Fedora. It makes the UX much more better than apt for daily usage.
My favorite: Single binary Hashicorp Nomad, the same binary for client and server! Runs without sudo, straight out of /tmp.
sudo make install
also it's really great when `sudo make uninstall` works