How do I set moral lines I won't cross at work?

You have done the hard, honest work of looking at what your job costs you morally, and you have drawn your lines. That clarity is rare and valuable. Most people never stop to figure out what they will not do. You have, and it will steady you when the pressure comes. The lines matter most on the day they are tested, when crossing would be easier or more rewarded. That is when clarity earns its keep. Because you decided in a calm moment, you will not have to figure it out under pressure. You will already know. Trust the version of you that drew those lines. He was thinking clearly. Keep the lines alive by revisiting them now and then, especially as the work changes. Say them plainly to yourself so they stay sharp. And if you ever feel one starting to blur, treat that as a signal to stop and look, not to push through. You have built a real spine for your working life. Keep it strong by using it.