You can give calibre an alternate location for its temporary files via the CALIBRE_TEMP_DIR environment variable, see ==>>
Environment variables
I would advise against using %systemroot%\Temp for this purpose. On Windows 10 at least, one has to jump though hurdles to open it, this to deter users from removing stuff Windows has written there, and I wouldn't 'trust' Windows not to delete data that an application might put there.
BR