> That isn't something I'd want to happen, it sounds like it creates a potential queue of scripts that will flood the system on start, if it works the way you described.

There are two options to fix it;

Disable persist so no catching up on missing scripts. Set OnBoot=5m so it gets ran 5 minutes after boot, so your script (say backup) is ran on boot first, then every time on schedule

Enable persist but just add sleep in ExecStartPre - very "cron" way but there is just no in-systemd option to enable "catch up" script to be delayed

Sadly no option to "run catch-up timers with delay" at least yet

> Then don't use @hourly, use staggered times, it's very easy.

Not in cron. In systemd it's just RandomizedOffsetSec=30m and it is "stable" - same host with same job will always have same delay so on multiple hosts it is spread nicely. There is also non-stable version