Cron job on docker (macos host)

I think you better ask Apple Support why this doesn’t work and how to troubleshoot Mac cron jobs.

Native Docker way would be to install side-car container running cron jobs:

  cron:
    image: nextcloud:apache
    restart: always
    volumes:
      - nextcloud:/var/www/html:z
    entrypoint: /cron.sh
    depends_on:
      - db
      - redis

see Docker examples

You might be interested on Nextcloud docker-compose setup with notify_push (2024) showing almost complete setup.