You must be really new here if you think losing the booru was anything but a bump in the road!
The hellgremlin apocalypses happened exactly the same way both times: Newfags started drawing more and more art that makes you angry, because outrage is the easiest way to attract attention. People who didn’t want to spend their time on a site more likely make them angry than happy started leaving, leading to a vicious cycle that made the fluffies more and more evil until making you mad was said to be the entire point of the fandom. Eventually even the hellgremlinists themselves grew sick of the masochistic self-aggravation, declared that fluffies were done, and left the booru a ghost town. If you think it wouldn’t happen a third time, you’d have to give some helluva convincing arguments to prove otherwise!
As for egoistic animals, fluffies aren’t animals. They’re biotoys, purpose-built for kindness. But the in-universe arguments one way or another don’t even matter - them being cute and friendly is the whole point of the fandom! If you like small animals that are just as evil and corruptible as humans, you’re not enjoying fluffies anymore. You’re enjoying hellgremlins. Or more likely, just being triggered into responding to them.
So in a nutshell, no, fluffies and hellgremlins cannot coexist. We’ve seen it before. It’s like allowing an unwashed, incontinent scatophile into a hot tub and then being surprised when only other filthy people want to use it anymore.