This article is related to the GTMetrix points assessment Reduce unused JavaScript which is usually found in the googletagmanager.com section
Follow the guidelines from https://developers.google.com/analytics/devguides/collection/ga4/basic-tag?technology=gtagjs
So each google analytics code is separate, and if you use multiple analytics code in one website, then this can be simplified to:
https://www.googletagmanager.com/gtag/js?id=UA-XXXXXX-13
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'UA-XXXXXX-13');
gtag('config', 'G-XXXXXXXXXX');
</script>