This code demonstrate how to make concrete inspector-like view from abstract protocol.

heterogeneous-inspector-view-sample.swift

// Swift 5.9
//
// Following code demonstrate how to implemnt inspector-like view from abstruct protocol.
// Somehow, @Binding will not work in this case under Swift 5.9


import SwiftUI

protocol Shape {
    func view() -> AnyView
}

class CircleModel: ObservableObject, Shape {
	@Published var count = 0
    func view() -> AnyView {
        AnyView(CircleView(circleModel: self))
    }
}

class RectangleModel: ObservableObject, Shape {
	@Published var count = 0
    func view() -> AnyView {
        AnyView(RectangleView(rectangleModel: self))
    }
}

struct CircleView: View {
    @ObservedObject var circleModel: CircleModel
    var body: some View {
        Text("Circle: count=\(circleModel.count)")
        Button("count") {
        	circleModel.count += 1
        }
    }
}

struct RectangleView: View {
    @ObservedObject var rectangleModel: RectangleModel
    var body: some View {
        Text("Rectangle: count=\(rectangleModel.count)")
        Button("count") {
        	rectangleModel.count += 1
        }
    }
}

struct ShapeEditorView<S: Shape & ObservableObject>: View {
    @ObservedObject var shape: S
    var body: some View {
        shape.view()
    }
}

struct ShapeView: View {
    @StateObject var shape = CircleModel()
    var body: some View {
        ShapeEditorView(shape: shape)
    }
}