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 enlarged view of the area circumscribed by lines 2-2 in FIG. 1.
The broken lines illustrate a display screen or portion thereof and portions of the graphical user interface and form no part of the claimed design. The dot-dash broken lines illustrate a boundary of the claimed design and form no part of the claimed design.