There is a trick used by IT professionals. The modern Microsoft Office "Click-to-Run" installer can be installed on a local drive. You can then use a symbolic link ( mklink /J ) to move the installation folder to a USB drive after installation.
PortableApps.com (search their forum – the official store only has LibreOffice, but trusted users share MS Office builds in forums). microsoft office portable best
You have three choices based on your risk tolerance and technical skill. There is a trick used by IT professionals