The 12 has the screen size of the 11 and the body size of the 11 pro. Seems like this generation, apple intentionally made the non pro better than what the 11
The evolution of iPhone screen-to-body ratios — shown by our sexy-ass graph
iPhone 15 Pro, iPhone 15 Pro Max Bezels Get Compared To iPhone X; A 30 Percent Decrease Over A Period Of Six Years