To be honest and this is purely objective, I didn't find the DB to be intuitive at all. I tried multiple times to track collections on it and found it pretty lacking.
I personally track my collection on Backloggery (https://backloggery.com/Gloves_Off).
I just don't think there's much value in us building a tool that other places do better because that's their main focus. There are plenty of collection tracking tools out there, and this is a place for video game discussion, generally speaking. We hang out, plays games together, and provide a forum for people to talk.
That said, I HAVE started my own person project where I'm tinkering with the idea of making my own collection tracker which would be "Doug's perfect tracker for Doug". I don't know that it'll be something I end up giving other people access to though, I have my own personal set of needs and wants, and this tool would very specifically fulfill those - for me and just me. I've made many tools before for myself and shared them publicly and they often become a bit of a pain to maintain cuz suddenly I'm supporting what other people want and I dunno if I wanna go down that road with this.
As for the forum software we're using here for VGS, it doesn't have anything that would support what you're looking for - no real way to have a games database and provide users the ability to say "I own this game" or "here's the list of games that I own". It's a forum, not a collection tracking tool. It COULD be built, but it'd have to be made custom. Either I (or someone else) could technically build it within the platform, and there are actually people you can hire to make stuff custom for your forum on the Invision (forum) software that we're using.
It may look like something that is relatively simple from outside, but building these sorts of tools isn't THAT straight forward, honestly. It takes time and effort, and a lot of both.