Why integrate it into social media, when the game is based of being one kind of social media? OK, maybe not, but the logic is there. It's a game only made possible because of the socialization. The rest is just addons to that one concept. (another hot topic: why would one user choose to enter a retro if that retro has a Discord guild which appears more active? it becomes the same thing, just different platforms, with pros and cons)
I don't think it's fairly possible to win back the previous audience of Habbo (including official, and retros). If you ask me, you should focus more on harvesting new users to the whole Habbo concept, but the retro community was never good at this. We failed to create an introduction to how Habbo works. Habbo figured it out, they used Frank to create interactive questions when you first register. Retros? You're sent into a room and expected to know everything and what every icon means.
I'm overthinking this by far but this is a strong observation I've made, based on what I've received as feedback from people who have never before played Habbo, who tried my HTML5 client as recently as last week. And the worst part is that I completely agree.
To move back on topic a bit: kids these days doesn't use Facebook, Twitter, etc. They use Tiktok and whatnot. Facebook is old news in 2021. Focus on knowing your audience to understand how to build up a higher traffic rate.