take a look at this post and thread. you just need to persist the file /var/www/html/cron.php
and adopt according your needsā¦ enjoy the official cron container!
I guess is a matter of separation of responsibility and a security concern. Nextcloud (or any other) application shouldnāt run on its host with administrator privileges, even more thereās a wide variety of hosts where you can have Nextcloud installed so it can be difficult to provide an implementation of such a feature for every available option.
I can understand as an end user it would be awesome to have this OOB, but for the dev tema there should be a balance between the ease of setup and effort to provide that. I assume thatās why ajax is the option by default (which is said āworks for a singleā), if you need a more advanced configuration then youāll have to do some tasks on your own specially to adapt it to your particular scenario.
Right now Iām struggling with the cronjobs myself so if I happen to find more useful details on how to solve this, will come back with a comment. So far the most insightful reading is the one suggested by @wwe in the post by @norsemangrey.