Returning a result from a command

[Anarios]

I'm building a simple Quiz app.

I have a command SubmitQuiz. It contains QuizId, QuestionIds paired with SelectedAnswerIds.

I need to save this submission and check whether SelectedAnswers match witch CorrectAnswers

And then I need to return a result (number of correct answers, number of wrong answers, and IDs of correct answers)

My question is - how should it be done? From what I've read - returning anything other than affected entity id from a command is a bad practice?

Should my [POST]SubmitQuiz controller first send a command to save quiz, and then send a query to retrieve result?

Should my client first send a POST with quiz, and then send a GET asking for result? (two network calls instead of one :( )

Where (in code) should the "scoring" of the quiz be done? In SubmitQuizCommandHandler, in DomainEventHandler?