well you can just set the env vars for the config directory and cache directory as described in
https://manual.calibre-ebook.com/cus...ment-variables
and run calibre like that. It wont be a "portable" calibre but it will use the specified config and cache locations.
There is an calibre-portable.bat file in the resources folder of the calibre install that does this for you but I dont know how up to date/maintained it is.