The linked post is about a new Metal-based renderer for OBS Studio on MacOS. The software you linked is for Linux.
A famously missing macOS feature. Loopback is yonder: https://rogueamoeba.com/loopback/
> the shortcut to stop screen recording on QuickTime sucks, it’s like CMD+CTRL+ESC
I just stop it from the menu bar, then on the resultant video press Cmd-T (trim) to lop off that footage.