When doing Excel imports always use temp objects. This way you can import the userrole just as a string. Then in the microflow to proces all the just imported temp objects you can retrieve the right user role based on the imported string and set the user role for that person. But this makes the import a two step proces. First import all in the temp objects and then the second step running a microflow that retrieves the correct objects and copy all the stuff over.
Regards,
Ronald