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 my new design; and,
FIG. 2 is a front view thereof, as shown in a display screen environment.
The broken line showing of the outermost rectangle in FIG. 2 illustrates a display screen. The remaining broken lines illustrate portions of the design. The broken lines in the drawings form no part of the claimed design.