There seems to be a crazy rat race for promotion. Doing you work doesn't cut it and my manager seems to want some mythical outcome. The "optics" seem to matter more to him than work. I constantly feel like I might get fired.
How do I navigate a career at Google? For context, I am a mid-level IC
Make sure they are not part of your org chain, and that there is a clear understanding of trust so you can talk openly about everything without any fear of retribution. It should be a safe place and a good mentor always respects that.
Your manager is pushing for something wonderful because he wants to be promoted. That doesn't mean that you have to give it to him. You just have to give him good work (at least as good as the average of your coworkers).
Now, it could be that you're never going to be able to fit in to that environment. Or it could be just your boss, and you're never going to be able to be comfortable working under him. I'm not saying that you should stay forever. If it's a bad environment for you, it's a bad environment for you. But be sure that's the case before leaving. And wait long enough to leave that you don't look like a flake - really short stints with an employer on resumes raise questions.
Unless you do gross misconduct, Google is one of the hardest companies to get fired from. Don't worry much about that. Even if you are a bad engineer, there are people worse than you in Google, and they keep their jobs.