Convert XLSM to MPP

Microsoft Project supports XLSX and XLSB formats from Microsoft Excel and can use the data from them to create a new plan file through an import wizard. It does not support XLSM files though, which are Excel spreadsheets with macros enables. You have to first disable the macros and re-save your .xlsm file as .xlsx file in MS Excel before you can import it to MS Project. No direct way for xlsm to mpp conversion exists.

Simply put, it is impossible to convert XLSM to MPP directly.
Thus, there is no so-called xlsm to mpp converter or a free online .xlsm to .mpp converter to be found.