The ornamental design for a displayscreen or portion thereof with graphical user interface, as shown and described.
The sole FIGURE is a front view of a display screen or portion thereof with graphical user interface showing my new design.
The outermost broken line rectangle illustrates a display screen or portion thereof and forms no part of the claim. The remaining dash-dash broken lines represent portions of the graphical user interface that form no part of the claimed design. The dot dashed lines which define the bounds of the claimed design form no part of the claimed design.