@ParryMe that’s a great question and use case for using Service Hub + Reports.
This may not be exactly what you’re looking for, but in this similar question I offered a workflow solution for when customers replied “thank you” in the email. That made me think there may be a workflow option for opening a new ticket if the previous ticket was already closed and they reply to an email. That’s where I’d personally start.
I also found this thread that’s more similar to what you’re asking, in regards to older tickets. That may also inspire a solution.