You have errors in your code:
Is your code all in one file? If so, you are mixing frontend (wix-users) and backend (wix-users-backend) code together in the same file.
Setting wixUsers2 from wix-users-backend in a frontend file will result wixUsers2 being undefined - which is exactly what the error message is telling you.
Refer to the Corvid documentation for details on how to code in Corvid. Refer to the wix-users-backend API for details on how to use the Wix Users feature in backend code.