I still like Excel for certain things but I don't know why you wouldn't just use Pandas instead of this and cut out Excel.
Libraries like xlread and xlwrite can and would be one way to automate such processes. Xlwings can too. I think that Xlwings can do macros where the others can't though
First sheet is usually raw data in standard rows/columns, second sheet would have the cells I need, etc a cell for sum of x columns from sheet 1.
Then use panda’s to get the data, and feed it through jinja2’s template render function.