I mean, you’re free to be skeptical, but there are plenty of examples of appointed judges ruling against the interests of those who appointed them. It’s rare-ish, but only insofar that appointed judges usually align in their interpretation of the law with those who appointed them, for obvious reasons.
Biden isn’t some left-wing ideologue; he throws the occasional bone to the Progressive wing of his party, but the vast majority of his appointments have been milquetoast Democrat standard.
I don’t know much about Corley, but if she was as aggressive with her stance on merger law as Khan is, I find it hard to believe she wouldn’t have granted a Preliminary Injunction when she heard the class-action lawsuit. But who knows, we’ll see in a week regardless.