Ensure that all Cron jobs work correctly I have a Mobile APP with a Drupal 8 admin backend and I have almost 20 cron jobs running at least 15 times on the day. I'm using Ultimate Cron and Advanced queue modules for handling this. I know that to ensure that all crons running properly, the website should be opened at least once a day or make the crons on the server not on the Drupal site. But, my solution is to create one cron job on the 
server hitting the website base url to just ensure that all crons will run. So, my question is, does this solution work?
Maybe.

Considering there are 20 cron jobs and they all run 15 times a day and you’re using advanced queue, I would make sure to test in your production environment timeouts and memory issues. 

Personally I would use cron + drush making sure the php.ini for command line PHP has more than enough resources to accommodate whatever it is you’re doing. 

drush cron-run


https://cgit.drupalcode.org/ultimate_cron/tree/ultimate_cron.drush.inc?h=8.x-2.x#n77