Link? I'm not entirely sure what you're talking about.
Taking a slight XY approach:
en.wikipedia.org
Maybe the Downstream Keyer plugin can do what you want?:
This plugin adds a Downstream Keyer dock to OBS studio.
obsproject.com
Make a scene to be your lower thirds content (or wherever you want it to be on the screen), and use DK to put it on top of your otherwise-finished content. You can even switch scenes like normal, and the overlay stays there.