So what I'm trying to achieve is a borderless console window.
The simplest and most obvious thing I could think of was to use SetWindowLongPtr(hWnd, GWL_STYLE, WS_POPUP);, but it seems that it produces some weird glitches on the window. To me, it seems like like the borders on the window are somehow cached or something.
Using SetWindowPos() does not help.
I've tried using SetWindowRgn(), but it seems a bit hack-y, and I do believe that it won't work if the user has a different resolution from mine, or a different window size, etc.