Hi @Anonymous
Another logic you can give a try is
1) Get all emails from Sent Items folder in outlook
2) Loop through all mails from sent items and check whether the mail with that subject starting with Re exists in Inbox, if yes it means mail has received a reply , else it has not received a reply.
See below flow design for better references:
expression: concat('Re:',items('Apply_to_each')?['subject'])
expression: length(outputs('Get_emails_(V3)_2')?['body/value'])
Note: Replied mail has Re at start of subject line
