Recommended approach to adding web pane to Excel worksheet

Question

We are using the Javascript API to write an Excel add-in. The app runs well in the task pane. We are making good headway on that, but there is a specific feature we want to support that is challenging to find an answer for:

How can we utilize the Javascript API to embed a web pane within a sheet in Excel? We would have a set of html content we would want to render within a web pane. It would be html-based text that, once dropped in a web pane, would pull in more Javascript to render a visualization. For simplicity sake, think of a button in the task pane for our add-in that, when clicked, drops that html into the highlighted cell on the worksheet.

Separately, is it easier or more challenging to have a web pane that essentially a web browser view?

We believe that "Content Office Add-ins" (https://learn.microsoft.com/en-us/office/dev/add-ins/design/content-add-ins#implementation) makes this potentially possible, but I would love clarification.

Thank you in advance.