How to automatically extend a pie chart to include categories when they have values

I have a pie chart on a pre-defined table with 15 categories where the data will populate over time (presently only 3 are populated) in descending order. As some categories will be blank/zero for a while, I'm trying to find a way to avoid showing the blanks/zeros on the pie chart. As I am trying to display the legend on the pie chart segment, any zeros cause the remaining labels to appear grouped together and rather messy. I would therefore like to hide the zero data from the pie chart so the labels do not appear, or to automatically extend the range to only include all non-zero values.

I found the following formula which, when used as a named range, automatically extends a list for data validation:

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I don't know whether there's a similar formula or whether a few lines of VBA are required to run whenever the chart or data worksheet are selected..?

Any chance of help, please?