If your newly-created Office Microsoft 365 Group's OneDrive for Business file Document library was not created properly, and you see "We're setting up your group files..." in a loop when trying to access it, try the following steps:
...
After performing these steps, it may take 5 or 10 minutes, but your group's OneDrive for Business Document library should be created properly. If not, please submit an ITS Service Desk Request.
...