I checked out this section when it was first deployed. I then compiled a list of what I thought would be obvious features and customizations needed to make it usable and provided that here in this feedback forum.
https://aqua.hsduabhb-nmzhi.cf/groups/SteamLabs/discussions/18/4365752248008425324/
It's been almost two years now, and it appears NOTHING HAS CHANGED! Seriously, just remove the DLC hub if you aren't going to deploy basic obvious features like hiding DLC already owned, or games not owned. This section is a waste of data on your client and servers if you aren't going to develop it any more. Not to mention how absurdly insulting it is to deploy this new feature nearly 2 years ago, ASK FOR FEEDBACK, get that feedback, and abandon the feature like it never existed!