Is it possible to create my own windowing system from scratch on MacOS or we have to use frameworks to make graphics?

Hello, I'm really interested in computer graphics. I started to learn how to create a window in objective-c with cocoa but I would like to learn how does it work exactly. So I've read about X11 but to create a window we still have to install XQuartz. I would like to learn how to create my own graphics from scratch even if it requires a lot of time. Do you have any suggestion to learn more about how does windowing system works on MacOS or we have to use frameworks and programs to make everything work? And if it is not possible, can you explain to me why we can't do that or what makes it that complicated? Thanks in advance.