If you want to create a view that shows all tickets that are unread and have not been read for 24 hours, you can create a trigger with the following conditions:
Meet ALL Conditions
- Ticket: Status less than Solved.
- Ticket: Hours since assignee update > 24.
- Ticket Tags: contains at least one of the following tags: mrr-unread.
If you have not heard a response from the ticket requester in 24 hours and the ticket is tagged unread it will appear in this view.
You can use the same logic in automations.