The path ist:
C:\Users\constantin\AppData\Roaming\Python\Python310\site-packages\six.py’
And this is exactly the problem. Probably you have installed the modules first as “constantin” and then (after you saw that Robotmk cannot be started) as Admin - but from this shell the module seemed to be installed already.
=> Try to rename/delete the Python folder in your profile and install the modules again from the admin cmd.
If you execute the Python commands again, six should be shown unter Program files/Python/....