I just wanted a quicker way to bring up the gnome-screenshot app.
So I went to keyboard in Settings. Stroll to the bottom to click onto add(+).
Name: Screenshot
Command: gnome-screenshot --interactive
Shortcut: Alt + p
It work like a charm. None of the build-in Screenshot Shortcut keys didn't work for me. I couldn't change or delete those settings. So I made this one. It work's that's all that matters.