The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
FIG. 1 is a front view of an embodiment of a display screen or portion thereof with graphical user interface of the new design;
FIG. 2 is a front view of a second embodiment thereof; and,
FIG. 3 is a front view of the second embodiment with additional broken line subject matter.
The outer broken lines show a display screen or portion thereof and form no part of the claimed design. The remaining broken lines show portions of the graphical user interface and form no part of the claimed design.