Disabling cookies in Google Analytics - gtag.js

Question

I am looking for a way to disable the cookies set by Google Analytics. I found some infos in Google's devguides: https://developers.google.com/analytics/devguides/collection/analyticsjs/cookies-user-id#disabling_cookies

Here it says that I should add the following code:

ga('create', 'UA-XXXXXXXXX-X', {
  'storage': 'none'
});

But where exactly? I already tried to add it inside the tracking code:

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-XXXXXXXXX-X"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-XXXXXXXXX-X');


  ga('create', 'UA-XXXXXXXXX-X', {
  'storage': 'none'
});
</script>

I'm grateful for every clue.

Answer 1

Given you use gtag.js (based on your example):

window.dataLayer = window.dataLayer || [];

function gtag() {
    dataLayer.push(arguments);
}

gtag('js', new Date());
gtag('consent', 'default', {
    'ad_storage': 'denied',
    'analytics_storage': 'denied'
});
gtag('config', 'xxx');

https://developers.google.com/tag-platform/devguides/consent#set_consent_defaults