SPO Comms Site - Hero Web Part - Open Internal Links in New Tab

Matt9915 You may already know that it is not possible to open the internal links in new tab using SharePoint OOTB capabilities. URL shortener is one way to do it (& you are unable to use it).

So, that leaves you with using custom SPFx web parts or extensions:

1. Use SPFx application customizer to inject custom CSS/JS on all modern pages
2. Use Modern script editor web part to inject custom CSS/JS on single page
   • Script editor web part for modern pages - You have to download the code & generate SPFx package (.sppkg) file
   • Modern CEWP by SPJS - You can directly download the SPFx package (.sppkg) file - not trusted maybe as they haven't shared the code used for SPFx web part

Once you get the .sppkag file, you have to deploy it to tenant app catalog or site collection app catalog as per your needs.

Then you can add & use the modern script editor web part on site pages like any other web part in SharePoint.

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.  

Related Read:

1. How can I include the same JS and CSS files on multiple SharePoint Modern Page? 
2. SharePoint: Configure Navigation Links to Open in a New Tab 

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