systemd was created to solve the problems of a directory full of shell scripts. A single shell script has completely different problems. And traditional init uses inittab, which is not /etc/init.d, and works more like runit.

runit's approach is to just keep trying to start the shell script every 2 seconds until it works. One of those worse–is–better ideas, it's really dumb, and effective. You can check for arbitrary conditions and error–exit, and it will keep trying. If you need the time synced you can just make your script fail if the time is not synced.

traditional inittab is older than that and there's not any reason to use it when you could be using runit, really.

yeah, many options that are complicated beyond the understanding of the distro maintainers, and yet still don't allow expression of common semantics required to support network services reliably

like "at least one real IP address is available" or "time has been synced"

and it's not esoteric, even ListenAddress with sshd doesn't even work reliably

the ONLY piece of systemd I've not had problems with is systemd-boot, and then it turned out they didn't write that

Same. I run a server with a ton of services running on it which all have what I think are pretty complex dependency chains. And I also have used Linux with systemd on my laptop. Systemd has never, once, caused me issues.