How do I lead a kitchen team through clashing personalities and pressure?

You can run the line, the cooking and the flow you have got. What tests you now is not the food; it is the people and the pressure, and that is the harder half of leadership. Nobody masters that quickly, because every crew is a new mix of humans. Personalities test you because leading is not about making everyone the same; it is about getting different people to pull together when it is hot and loud. The pressure will always be there. What changes is your steadiness inside it, and steadiness is caught from you by the whole line. If you hold, they hold. Small step: pick one cook who tests you most and learn what actually drives them, pride, fear, wanting to be seen. Lead that person as they are, not as you wish they were. You have mastered the line. Now you are learning the people, and that is the part that makes a real chef.