You can use the JFree charts module. The typical usage scenario says ‘Create a .png image of a chart and use it in a pdf export’. There is one widget in appstore => https://appstore.home.mendix.com/link/app/3011/
You need to do the chart configuration, should map the non persistable entity, in the charts module. But currently this widget will support only for few charts like bar, Line and pie charts.
There is one widget in the appstore that stores the graph so it can be used in document templates: https://appstore.home.mendix.com/link/app/3011/TimeSeries/JFree-Charts-(.png-images)
May be you can use that one or adapt it to your own needs.
I used the ChartJS Widget (https://appstore.home.mendix.com/link/app/1712/) feature to create a Base64 image, and used that in the PDF.