to have a fully portable, unlicensed, offline Excel.
The closest safe alternative is LibreOffice Portable – it’s free, works like Excel, runs from USB, and won’t infect your PC. excel portable descargar gratis
While not "portable" in the sense of a .exe file on a thumb drive, these options allow you to use Excel for free without a full local installation: to have a fully portable, unlicensed, offline Excel