@laughsmile the (new) Excel Writer is perfectly capable of appending a sheet to an existing excel file with a Macro in it:
Which version of KNIME are you using?
Also the Excel Sheet Appender (XLS) (deprecated) is still very much with us it is just not being initially suggested in the node repository. Though I think it was not able to append XLSM files.
Maybe you can post an example (file) or workflow without sensitive data so we could give it a try. Or check this example:
