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 an additional front view thereof showing additional, unclaimed subject matter.
The dot-dash broken lines define the bounds of the claimed design and form no part thereof. The dash-dash broken lines in FIG. 2 show a display screen or portion thereof and portions of the graphical user interface and form no part of the claimed design.