I really love this node because you can fully customize the graph beyond CSS capabilities. Recently, I was generating a Heat map with it and I realize that one cannot download the graph as a vector for further working with it.
Unfortunately, I do not believe you are able to export the view as an SVG directly, but you can add a tooltip to download a PNG of the view (which you can then convert to SVG if needed)
Ok, I give up on the topic, which is beyond my knowledge area.
However, I leave all the data whether someone, smarter than me, can manage to get this working.
There is indeed a SVG rendering possibility with Echarts. However, it requires that KNIME have the default module or KNIME should allow the users to install modules.