Hi,
I can offer you some guidance. you might need do use the AnyChart widget https://docs.mendix.com/refguide/charts-any-configuration/
what you are looking for seems similar to this example: https://stackoverflow.com/questions/66184311/plotly-annotate-marker-at-the-last-value-in-line-chart
you can use the development mode of the chart widget to fiddle with the structure. I recommend the plotly reference: https://plotly.com/javascript/reference/