The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
FIG. 1 is a front view of a display screen or portion thereof with graphical user interface, showing our new design; and,
FIG. 2 is a front view thereof, in which a display device in broken lines is provided to illustrate an example environment.
The broken lines showing the display screen are included for the purpose of illustrating environmental structure and form no part of the claimed design.