Hi TheWhiteSword

Is both simulator set to Physical Size (cmd+1)?

It depends on your code but I think you may have use .frame(). If you had, I will try to explain. (if you have not then ignore and give us sample code to see want you mean).

If you have a square and run on both iPhone 11 and 11 Pro Max

struct ContentView: View {
    var body: some View {
        Rectangle()
            .frame(width: 200, height: 200)
    }
}

then the square looks smaller on the bigger (the Max) screen but it an optical illusion because there is more white space between the square and the edge of screen, however the square itself is actually the same size. If you want the square to be the same distance from the edge then you have to increase the size of square when on a bigger screen

struct ContentView: View {
    let width = UIScreen.main.bounds.width - 170
    var height: CGFloat {
        width
    }

    var body: some View {
        Rectangle()
            .frame(width: width, height: height)
    }
}

This really depands on what you want to do, but as long as it look good on both eg not clipped etc then it down to design. Also have to watch when using .frame() as you may run it to going off the screen in smaller iPhones eg iPhone 12 Mini