The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
FIG. 1 is a front view of our design for a display screen or portion thereof with graphical user interface; and,
FIG. 2 is a front view of a the design of FIG. 1 in a different environment.
The outermost broken line rounded rectangle showing an electronic device illustrates environmental subject matter. The broken line showing a display screen, and all other broken lines showing portions of the graphical user interface illustrate portions of the article. None of the aforementioned broken line subject matter forms part of the claimed design.