What's the recommended way to update a chart?

I’ve developed a few shortcut automations that plot line graphs with Charty. Each day, one automation gathers a new data point, and then a second automation is supposed to update the chart (which is then shown in a widget).

However, I’m having trouble. My current approach is to create the chart anew each time, using a fixed ID and ticking on the “replace if needed” option in the “New chart” action. The problem is frequently I get duplicate charts, and sometimes the new chart doesn’t render with all the styling options from the various “Style” actions.

I’m not confident I’m approaching this in the intended way. How is one supposed to update an existing chart? Should I be replacing just the data series? Or doing something else? Thanks.