A shared kitchen works better when people know which ingredients, utensils, and storage spaces matter to each other. Assumptions create more friction than a short conversation.
Discuss what you are comfortable sharing and what needs separate handling. Dietary preference and food allergy are different concerns, so be specific about the reason for a boundary without treating either as a joke.
For meals, look for a common base when it suits everyone: pasta, potatoes, a bean dish, or vegetables with separate toppings. You do not have to eat identical plates to share dinner, but each person should have enough food they actually want.
Keep the plan simple on busy nights. A familiar shared dish may be more useful than making every meal an attempt to change somebody's preferences. Good arrangements are the ones people can follow when tired.