How can I stay free no matter what happens at work?

You have arrived at a truth that sets you loose: no circumstance at work can touch the freedom of how you meet it. Deadlines, difficult people, setbacks, none of them reach the core of your choice. That is real freedom, and it does not depend on the day going your way. This is not pretending things are fine. It is knowing that your response is yours, always. Something outside you may shape the situation, but you shape what you make of it. When you hold that clearly, the usual threats lose their grip, because they were only ever pulling on things you can release. Keep it strong by using it. Each time work presses on you, meet it as the free person you are: steady, chosen, unforced. The more you practice that stance, the more natural it becomes. You already know where your freedom lives. Live from there, and almost nothing can shake you.