I am answering my own Question.
This is my experience:
I installed Windows 10 Pro 21H1 in VMWare.
I downloaded Windows 10 S installer
It downloaded Win10S
Then it asked "Choose what to keep" and the only option was "Nothing". And there was written "Your apps and settings cannot be kept because Windows is installed in unsupported ...
All Windows installers only touch the system drive for software installation.
The installers don't touch other disks, unless, for example,
a specialized partition is required for recovery. But even then it will
only reduce the size of some existing partition to create the
new partition, and will not delete existing partitions.
An exception for Windows S ...