Is it possible to create a combination of Line and Bar chart in Interface Designer?

Hi there—it isn't currently possible to overlay data with multiple visualization types (bar + line) on one interface chart, though I could absolutely see the benefit of having this functionality! I'd be glad to surface this to the team and I'd also encourage you to add your vote to existing posts like this one in our Product Ideas section.

You could also explore creating something similar via the Vega-Lite extension to generate this data (Community posts like this one can offer inspiration for the breadth of options available). You could then create a shareable extensions dashboard (which is a read-only base share link) by following the steps outlined in this support article to include the URL on your interface. While this won't display the chart directly on your interface, you can still access it from your interface by clicking the link as needed. Hope that this can help to clarify some options here!