Comment by einpoklum
> fully customizable
There are all sorts of customizable. CachyOS' use of that word is rather inspecific. I guess it means the compilation flags are better customized for your CPU, plus it is easier to choose a kernel with a different scheduler enabled. So, "more customizable" in that sense.
Of course you could ask whether you could 'customize' your distribution not force you to use systemd. Most popular distributions fall flat on that one, I'm afraid...
Most distributions also don't allow to 'customize' any of the following:
- compiler used for building the distribution, - libc implementation, - C++ standard library implementation, - coreutils implementation, - system shell, - kernel (e.g., using Hurd), - PAM or equivalent, - util-linux, - package manager,
and so on. systemd is just one more thing in that looong, looong list.