So, I decided to build goguma, a free, open-source Mac menu bar app that wakes your Mac only when a cron job/automation is scheduled to run. Unlike caffeinate, Amphetamine, or Adrafinil, which can only keep an awake machine awake, goguma can wake a sleeping machine.
It automatically imports all your jobs across launchd, crontab, Hermes, etc, alongside detecting agent activity through hooks. The Mac menu bar app will also show you which job it'll next wake for.
It remains safe by skipping wake-ups if it's lower than a battery threshold, and lets the mac sleep if it starts overheating.
Happy to hear any feedback and suggestions!