They show up in the quiz reports, but you would still have to visually scan down all the rows of the report.

Or, you could do it with https://moodle.org/plugins/report_customsql, and a query like:

SELECT
q.name,
COUNT(1) AS Number_of_attemps,
SUM(WHEN qa.flagged = 0 THEN 0 ELSE 1 END) AS Number_flagged

FROM mdl_quiz_attempts quiza
JOIN mdl_question_usages qu ON qu.id = quiza.uniqueid
JOIN mdl_question_attempts qa ON qa.questionusageid = qu.id
JOIN mdl_question q

WHERE quiza.quiz = :quizid AND quiza.preview=0

ORDER BY q.name