The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown.
The single FIGURE is a front view of a display screen or portion thereof with graphical user interface, showing the image of my new design.
Broken lines shown in the FIGURE illustrate a display screen or portion thereof, and form no part of the claimed design. Other broken lines shown in the FIGURE illustrate portions of a graphical user interface that form no part of the claimed design.