And which of these announcements really required manual intervention on a VPS running a webserver? A webserver clearly doesn't use a GUI library like wxwidgets, probably won't run keycloak, and the GRUB change depends on your environment, with good chances that it will still work without re-writing the bootloader.

In any case, just subscribe to the arch announcements mailing list and you'll get an email notification in these cases. Not sure if I would put pacman -Syu into cron though.