A specific hub area is great for focusing on DLC for one game at a time, but it won’t be as helpful/usable unless it incorporates some of the already-requested refinements such as respecting Ignores and incorporating filters like the Store search has.

While it would be a fundamentally different approach, I would actually prefer simply adding a filter(s) to the Store search itself instead of a separate hub. SteamDB has this functionality (“DLCs for owned games”), and Steam should as well. Pros and Cons to either approach, but incorporating this into the standard search filters would provide native support for all the other filters already available so one can, for example, easily filter out owned, ignored, wishlisted, or otherwise not preferred DLC.