We can develop custom chart widgets from Highcharts samples.
(Note: OutSystems Platform only offers the license of the Highcharts version it includes)
You can refer to the Highcharts samples in the following document (index.htm).
https://code.highcharts.com/zips/Highcharts-6.1.4.zip
After that, you can copy and paste the JavaScript source code from the index.html file or Web Browser, and create your own Stream Graph or any other one which-ever you like the most.
Preview Link :- https://personal-vupnklpl.outsystemscloud.com/StreamGraph/WorldMapScreen?_ts=637993623927609313