I feel Dev Negi is not convincing

Dev Negi as Playback Singer has some moments that stayed in my mind. For me, it does not feel very real in many scenes. Many moments pass very fast, and I do not remember much after them. I do not hate it, but it did not pull me into the story. Some emotions are too simple, and I cannot believe the character enough. The role needs more detail, but the performance stays on the surface. Maybe other people will like it more, but this is my feeling.