If you run your code on a Windows computer with Excel installed, you may also want to take a look at the xlwings package. It uses your Excel as an "engine" for reading and writing Excel files. On large files, it is faster than openpyxl despite the extra overhead of running an Excel instance.

And it works in both directions, so you can call functions in your local python code through user defined functions in Excel. You can for example have an input table in an Excel workbook and have your python code generate new output in an output table as soon as you make a change in the output table.

The downside is that needs Windows and Excel, and that heuristic malware scanners sometimes flags it. I have had our IT department contact me once because they got an alert. So if you use xlwings for file reading and writing, you may need a fallback to openpyxl in your code.