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 our new design; and,
FIG. 2 is an enlarged partial front view thereof, shown separately for clarity of illustration.
The dashed broken line showing of the display screen forms no part of the claimed design. The dot-dashed broken line showing represents a boundary line excluded from the claim.