Using wkt://LINESTRING to create hatched polygon border?

Question

I am trying to create this GeoServer layer style:

Obviously I can't achieve this by using shape://slash with PerpendicularOffset since that produces the following:

I have found previous Q&As like Using Math in SLD file - wkt which suggested to use custom geometry defined with wkt://LINESTRING but when I try it, the particular geometry does not render at all.

Is it only possible to use WKT geometry with a GraphicFill instead of GraphicStroke or what am I doing wrong?

<LineSymbolizer>
    <Stroke>
        <GraphicStroke>
            <Graphic>
                <Mark>
                    <WellKnownName>wkt://LINESTRING(0 0, ${sin(Orientation) * 200} ${cos(Orientation) * 200})</WellKnownName>
                    <Stroke>
                        <CssParameter name="stroke">#DC33FF</CssParameter>
                        <CssParameter name="stroke-width">2</CssParameter>
                    </Stroke>
                </Mark>
                <Size>10</Size>
            </Graphic>
        </GraphicStroke>
     </Stroke>
     <PerpendicularOffset>-5</PerpendicularOffset>
 </LineSymbolizer>