Moved from cronie to systemd timers because they are resilient to system startup times. My backup strategy is to create a borg archive entry every day at a fixed time. With cronie the system needs to be running at the scheduled time, but systemd timer tolerates this and runs the service as soons as the system is available.
Btw this is my repo for the backup automation: https://github.com/gchamon/borg-automated-backups