Content Viewer

You use the plugin “Content Views – Post Grid & Filter for WordPress” to output the list of posts including the “Read more” link. My recommendation would therefore be that you first contact their support: https://www.ads-software.com/support/plugin/content-views-query-and-display-post-page/

You can also have a look at what the WordPress documentation says about influencing the “Read More” links: https://codex.www.ads-software.com/Customizing_the_Read_More

Remember: what you want is in HTML terms the indication that a link should open in a new window/tab. This information is a recommendation for the visitor’s browser. The browser does not have to follow this recommendation. Many mobile browsers already suppress this recommendation, which is why your plan would probably only be applied to a fraction of your visitors.

Thank you Threadi. I appreciate you taking time to clue me in.