Archive items from done List

So we have a trello board and have a few things automated so make things more convenient.

At the moment we use a few different buckets on our main board. With the final stage being the “DONE” list. The tasks in the DONE bucket can stay there a little while, just in case. But now it’s piling up and we’d like to add an automation to it, but I can’t figure out how to do it.

In short: we’d like to have an automation that is along the lines of
“If a card is in” (list) “for longer than” (x amount) “of days” → action (move to/archive)

Is this at all possible within Trello?

Of course i can add a rule where - anything moved onto the list gets a new due date - and then a rule that - if the due date is met it is moved to archive. - But then I’d lose the current due dates of the items.