Filtering tasks down to a certain time range is not available in OmniFocus yet. You’d have to collapse all the groupings for anything over 2 weeks.
It’s not available in the OmniFocus 4 TestFlight for iOS/iPadOS as well. I’m thinking that such a feature idea might come in version 4.1 when Omni Group is able to break compatibility with OF3 and introduce new metadata that will offer this feature.