Adding a "Time Since Date" Filter to Reporting

As part of our workflow, we manually archive tasks that have been closed out for more than 30 days. I am trying to set up a dashboard where these 30+ days-since-completion tasks will be listed, for easier filtering and archiving. However, I realized there is no option to filter dates in an “older than X days” fashion.

The only available options are: “Within the last [time]”, “Within the next [time]”, “Between [date] and [date]”, and “On [date]”.

What I’m basically looking for is a “More than [time] ago” option.

Does anyone have ideas on how to achieve this filtering? Is it a popular enough idea that it might get some traction with the product devs?