Hi @Masor,
As you noticed, currently it is only available to get the respondents E-mail Address.
For Emails within your own organization, you could take use of Office 365 Users Action to get the User Profile, then use the Name field provided there.
But for the respondents who are outside your organization, there is no proper way to get the UserName, as the only available data that could be obtained from the Form response is restricted to the Emails.
Regards,
Michael