I want to capture all windows except my own window and I need this to be as fast as possible (in terms of FPS). Now, there are couple of similar questions already asked and answered, but none of them really satisfy my requirements.

Setting window affinity is not an option, because I want other apps to be able to capture my window.

I'm unable to find a single API that does this. So, maybe the only option is to capture all windows separately and then somehow merge then into a single image using each window's size, position and Z-index. There are dozens of APIs to capture windows on Windows. At this moment, Windows.Graphics.Capture seems to be a good one with C++ support, but I'm open to consider anything else if it runs on GPU and makes it easier to merge those separate windows.

Maybe merging/combining could be a separate question, but this way it has more context. However, I'll edit my question if needed.