read multiple .xlsx files and text files in a directory

[snippsat]

1) don't recommend pandas, but mostly because...
2) I'm not even really sure what it is  

From what I've seen it's basically numpy, but more complicated and without any additional benefits.

Ehhh then maybe look into it,it's for sure not just NumPy with additional benefits

That said Openpyxl is a great tool for working with Excel files.
It's a library that's specialized to work with Excel files.

Pandas is a great tool that can read a bunch of formats(can take some effort to install for beginners).
Need also to use Jupyter Notebook to get the most out of Pandas then a Dataframe look just like Excel.
Common Excel Tasks Demonstrated in Pandas

This task can solved both,so not so much to discuss about

[BNB]

Well, just an update, I have solved my issue with openpyxl but its just that openpyxl is not very helpful in saving images (as mentioned in its documentation) from original excel file and it disappears when you save the workbook.
Any other libraries that is compatible with xlsx files, can modify/append worksheets and save it in original form with images/formatting ?