Complex expressions are one of the things I don't like in cron. On Debian/Ubuntu servers, I bite the bullet with systemd timers. On my workstation, I have a personal job scheduler that feels easier and more fun to tinker with. The scheduler uses Starlark functions instead. For example:

  # Run if at least a day has passed since the last run
  # and it isn't the weekend.
  def should_run(finished, timestamp, dow, **_):
      return dow not in [0, 6] and timestamp - finished >= one_day

  (job
     '(next-minute-from
        (next-hour (range 0 24 2))
        '(15))
     "my-program")