Certain operations can't be app-only and require user interaction for auditing purposes, and group creation is one of them.
This looks like potentially the same issue: https://github.com/SharePoint/sp-dev-docs/issues/3799
https://github.com/SharePoint/sp-dev-docs/issues/3718
In this case the scenario you described is unsupported and you would need to make a feature request to change this. https://feedback.azure.com/