Edit: None of the answers I got work so I went ahead and filed a bug in KDE bugzilla: https://bugs.kde.org/show_bug.cgi?id=502901
Neither CTRL Q or CTRL W work for me. I set a hotkey for the window operations menu in Settings app > Shortcuts > KWin > Window Operations Menu, but then pressing the close button in the context menu that shows, closes the window of the other window I was focused on and not the debugger.
I’ve had the titlebar rule enabled for over a month and the debugger is literally the only window I have issues with. Titlebars are a waste of screen real estate and don’t look good imo.
Then just change the rule to not include the debug console…
How much “space” are you really “saving”? A centimeter? Anyway, it’s your computer, you do whatever you please to it.