I feel Jenny Cousins is not convincing

Jenny Cousins as Focus Puller has some moments that stayed in my mind. The role needs more detail, but the performance stays on the surface. Some emotions are too simple, and I cannot believe the character enough. Many moments pass very fast, and I do not remember much after them. For me, it does not feel very real in many scenes. This is only my personal view, but the performance changed how I enjoyed the film.