Show cookie consent on selected page

Hi, I tried your solution:

ppms.cm.api('openConsentForm', function(){}, function(){});

to show the form after page load. But this do not work. If I call this in the browser console, the form will appear.
I guess I have to wait for the API to be ready and therefore i put this call into

  document.addEventListener("DOMContentLoaded", function(){
    ppms.cm.api('openConsentForm', function(){}, function(){});
  });

but without luck. Is there a callback function which I can use for it?

Background is, since it is not possible to hide the consent on specific pages
like Privacy Policy or Impressum.

(or did this change menawhile?)
We use a link to another page where the user can modify the settings.
To avoid the user must click once more to get the modal open, we would like to show this after loading the page automaticly.