"The way you expect" is probably inconsistent and, upon closer inspection, completely broken.
There is a reason why systemd became the default and other niche init systems have faded into obscurity.
Sure, it may be more complex than your pile of shell scripts, but that's because it does the same things better, and has a lot more functionality that you will need at some point, and good luck replicating that by hacking shell scripts.
> There is a reason why systemd became the default and other niche init systems have faded into obscurity.
Yes, it is part of the Embrace, Extend, Extinguish strategy
You are framing this as the only choice being between systemd and shell scripts.
> "The way you expect" is probably inconsistent and, upon closer inspection, completely broken.
When I start a program, I want it to stay running. This is perfectly consistent and not broken.