Datagrid2 was rushed and initially launched with limited features. Over time its gotten a lot better, but a common approach to dealing with the shortcomings was to use an NPE approach to fetch and associate records to an NPE and then display those over the association. The new OQL View Entities offer a solution to this, but are difficult to implement and should be reserved for truly complex views or filtering rules. Currently, the only missing generic filter for datagrid2 is a switch or toggle filter. This does exist, but only as a dropdown and only for stored boolean attributes. Even if you assign a calculated boolean attribute, you are still stuck using a dropdown to change the filter, which IMO looks horrible and is not intuitive for end users. Instead, there needs to be native support for a switch/checkbox filter widget, allowing one click toggle filtering for the attribute or expression set on the switch filter.
I am still having to take the NPE approach just to achieve a single switch filter to toggle whether or not inactive/closed records are displayed.