Global shortcuts and screenshots are already available as standard features. The problem with your thinking is the system needs to be designed to have security

Global shortcuts and screenshots are already available as standard features. The problem with your thinking is the system needs to be designed to have security by default for it to have an chance of being secure. We know from X11 that "insecure by default" is a mistake that leads to everything breaking later when someone tries to hack it to actually have security. When everything is secure by default, you can still turn off the security checks and allow everything to get access to everything else.