Email writing to data to Excel sheet - Bypassing duplicates

Hello! I am a complete noob to Power Apps and just created my first cloud flow; Capturing outlook email details and adding them to an excel sheet. Works almost good, so far! The aim is to capture email subject, date, and sender, which it does.

What I would like to do is have it NOT capture duplicate emails or if someone replies to the email thread (currently takes any replies and adds them as an additional spreadsheet line). I understand that I need to filter our dups by using an Exception, but cannot figure out how.

Can anyone share a step-by-step? Text or video, either works! Appreciate it!