RuntimeError: Model class openedx.core.djangoapps.content_staging.models.StagedContent doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS

This happens to me when I do the openedx pytest:

pytest openedx

RuntimeError: Model class openedx.core.djangoapps.content_staging.models.StagedContent doesn’t declare an explicit app_label and isn’t in an application in INSTALLED_APPS.

This error is similar to the one discussed in Django Installed Apps Error after Quickstart on M1 - could you please review that thread and see if any of the issues there are what’s causing it for you?