The ability to get rid of this thing should be an option.
It’s because Youtube is not a true PWA, so you’re really just adding a shortcut to your homescreen. If the menu option says “Install App”, Brave recognizes the site as a PWA and no titlebar will show. If it instead says “Add to homescreen”, then it is just a simple shortcut.
It doesn’t act like a shortcut, it acts like a stand alone app. It doesn’t open in the browser, it doesn’t open multiple web pages, and the titlebar cannot be edited. The titlebar just won’t go away.