Hi Derek, I’m not sure what you mean by a merged Google Doc, but what you can do is insert a chart into a doc from a Sheet (screenshot below).

I’m not sure under what conditions it will automatically refresh, but if you sent a customer a doc and there was new data by the time they opened it, they can simply hover over the chart to refresh and fetch the latest chart data.

I’m not sure if this is what you’re after. Try and experiment with it a bit to see whether the doc auto refresh after some time.

Hope this helps.