The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
The FIGURE is a front view of a display screen or portion thereof with graphical user interface, showing our new design.
The inner large broken line rectangle shows a display screen or portion thereof, and forms no part of the claimed design. All broken lines within the display screen show portions of the graphical user interface, form no part of the claimed design. All broken lines outside the display screen shown environment and form no part of the claimed design.