You're going to need some way to identify which record is the latest in your data somewhere and have a filter on that instead. That way you won't need to change it every month (or whatever interval you're using)
Try linking your data records to a single record in a summary table and using a lookup field that only shows the last linked non-empty record. Be sure to link the records in the order they'd be created (earliest to latest) for your existing data so that it outputs the correct data. For new records you'd populate the link via an automation or something so that'd work fine
