Hi Jay,
The figure appears to be a dense contour plot or a heatmap with a high number of data points. Such plots can be very resource-intensive to render as vector graphics. This is because vector graphics are rendered based on paths, which are defined by mathematical equations. A dense plot with many data points requires a large number of paths to be calculated and drawn. Each data point or line segment in the plot translates to a path in vector graphics. When there are thousands or millions of these, the file becomes very complex, making rendering, processing, and exporting very time consuming.
To render it faster, the complexity of the image needs to be reduced if you want to export everything as a vector.
You could also try approaches to rasterize some parts while keeping the other parts as vectors to speed up the rendering process, but as far as I know, MATLAB doesn't inherently support it. You might need to export the vector content and raster content separately after which you can combine them.
The following MATLAB File Exchange contribution might also help you:
