How to insert a custom Script inside a Modern WebSite page ?

Thanks for the mention RobElliott 

Roberto Ialino You can inject custom JavaScript/CSS on modern pages using SPFx. Check my answer for more information at:  Running modern 2022 native Web Components in Microsoft365/SharePoint Online 

Note: DOM manipulation & CSS customizations are not recommended by Microsoft and some of your customization may break if Microsoft changes HTML element id/classes in new release updates.

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