The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
The FIGURE is a front view of a display screen or portion thereof with graphical user interface showing our new design.
The outer perimeter illustrated by a pair of broken lines in the FIGURE depict a display screen or portion thereof and forms no part of the claimed design. The remaining broken lines in the FIGURE depict portions of the graphical user interface and form no part of the claimed design.