create a custom shortcut (as an example Super+Print) with the command: xdotool exec flameshot gui
As a result, it loads "flameshot gui" without creating a terminal session that could appear in front of the screen's part you want to take as a screenshot.
possible smooth solution:
As a result, it loads "flameshot gui" without creating a terminal session that could appear in front of the screen's part you want to take as a screenshot.