> In cron, you basically have to either use your configuration management to generate those times, or have a random delay script running before the command

Nope. From crontab(5)

  The  RANDOM_DELAY variable allows delaying job startups by random amount
  of minutes with upper limit specified by the variable. The random  scal‐
  ing  factor  is  determined during the cron daemon startup so it remains
  constant for the whole run time of the daemon. 

[0] <https://stackoverflow.com/a/34815984>