Hi @Anonymous,
I would like to know more details about your scenario. What are the two lists Quiz Results and QuizStatus?
According to your description, it seems that you are trying to create a flow to update a column “Level1Complete” in a list when all quizzes have been taken then send an email.
To check whether all the fields in a list have been taken, we could try to combine functions “and” and “empty”.
I have made a small test on my side, the function I am using is:
@and(not(empty(triggerBody()?['Title'])),not(empty(string(triggerBody()?['opcy']))))
PS: the column ‘cpcy’ is of type float, while a string is asked in the empty function so I use string function to convert it to an expected type.
The flow might be configured likes below:

Please take this for a reference.
Reference material:
https://docs.microsoft.com/en-us/azure/logic-apps/logic-apps-workflow-definition-language
Best regards,
Mabel Mao