Hi there! Currently, Outlook does not offer a built-in option to set a cleanup rule for 10 years. The available options are limited to 3, 6, or 12 months1.
However, you can use a combination of rules and the AutoArchive feature to manage older emails. For example, you can create a rule to move emails to a specific folder and then set the AutoArchive settings for that folder to delete items after a certain period2.
As for future updates, there’s no official information yet on whether Microsoft plans to introduce a 10-year cleanup rule. It might be helpful to provide feedback to Microsoft through their support channels or user forums to express your interest in this feature. Please accept answer if it helps.