We don't know enough specifics about the OPs situation, but sometimes discouraging people from making a complaint and "keeping their head down" really isn't the way to go. I have a fairly visceral response on reading this sort of advice, because it's a commonly held belief that often works against people. Where is the line here? To use a crude example, if we were talking about sexual harassment, would the advice be the same?
Sometimes, being a brilliant employee doesn't matter (and might be the reason someone is being targeted in the first place). Allies can provide cold comfort, and unwittingly make things worse, particularly in a fear-based workplace where everyone is looking after their own interests. These things are really complicated and there is no one-size-fits-all solution.
I do agree that when you make a formal complaint against your employer, it is usually the point of no return. You should expect to be leaving your job - the goal should be to do so on favourable terms. While you may want things to go back to the way they were, you also need to consider whether it is realistically possible to change your situation though other means. One trust is broken, it can be extremely difficult to build it back. And if the workplace culture is deeply dysfunctional, you probably won't be able to fix it.
I agree that people should manage their expectations of "justice" in these situations. I wouldn't say that there is "no justice", but that it is not achieved in the form of people becoming enlightened or realising the error of their ways. It is achieved through financial compensation or in the case of criminal misconduct, more severe forms of punishment. It is undeniably risky to attempt to achieve such justice, but it is possible. It's a very personal decision. Only the OP knows the full facts of their situation.
OP one thing that's really important, that probably hasn't been said enough here...you need to prioritise your health. If you need to take time off or see a therapist or whatever, do it. If you can ramp up your exercise and eat better, do it. You are probably on the verge of burnout (if not there already) and it is true that this can really distort your thinking. Everything might seem like the WOSRT THING EVER right now. Your mental health is the foundation that any action you take is built on. Even if you decide to start applying for other jobs, you may struggle with this if you are feeling emotionally exhausted.