That is, as live installation: all the settings and changes must be preserved, applications installed and uninstalled, etc … as if it was installed on a normal, internal drive.
How to? WindowsToGo has become discontinued.
Is there a concreate, real instruction? Not a threory as in “you do it this the same way you would in case of an internal drive”, as this way it won’t work.
This sounds like an XY problem. If you’re looking for a portable Windows environment you can take to multiple devices, you probably want a WinPE setup, like Hirens.
If you are out of space/ports/whatever to install on an internal drive, that’s something you should probably attack directly.
None of these