I used to have the following shortcut mapped to META+SHIFT+S to replicate Windows behaviour to have a selectable region to auto copy of the clipboard.
gnome-screenshot -a -c
The ironic thing is when I used to use Cinnamon as a desktop environment this worked 100% perfectly now running GNOME but still gnome-screenshot the capture is not copied to the clipboard.
If you are on Gnome 42, gnome-screenshot has been replaced. See How to call gnome42 built-in screenshot tool in scripts
So the GNOME-42 screenshot tool doesn’t appear to have a CLI.
I have worked around/ solved my problem by installing
Rebooting, and then going into settings auto copy image data and keybindings, SUPER+SHIFT+S