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 the claimed design.
The outermost broken lines in the FIGURE show a display screen or portion thereof and form no part of the claimed design. The five icons shown in solid line in the leftmost portion of the display form part of the claimed design. All other portions of the graphical user interface form no part of the claimed design.