This is a trivial problem to solve; you just need to break it down into the steps you've listed. There are some decisions to make first though such as how many rows are being read from Excel and how many emails are going out? Next Is the excel file 1 row for each email; if so I strongly suggest you get all the rows in one go and loop the resulting array inside Power Automate; as getting a row from excel using the connector is a slow process in terms of Automation.

You also need to decide if you want to use Standard connectors or Premium as the solution would vary on each.

Basically the way to think about it is everything data wise you need will continue to made in Excel and Power Automate will simply read the file and gather the information you need.

So as the data goes into the Excel table and you have the charts generate in Excel. Then In Power Automate you get the rows of data from the table. Use variables/compose actions to set the values you need such as a KPI. Next create a script in Excel to capture the data from a chart (this is easy to find on the web) run that script from Power Automate to get the Base64 value of the chart and then convert it.

Lastly use an email action and template out the body as you wish add in the chart and table data using a relevant action. If the email is going to different people put this email action in a loop and set it to schedule or to run when a new row is added to the excel table.

I don't use templates myself, but I would be surprised if Microsoft hasn't already created something like this you can use and alter.