下面是我解决这个问题的方法：
AppState.swift:

class AppState: ObservableObject {
    
    static let shared = AppState()
    init () {} // TODO: was private init, find out if this has benefits
    
    @Published var currentView: String = "login"
    // add rest of shared stuff below

AppDelegate.swift:

func applicationDidFinishLaunching(_ aNotification: Notification) {
        let appState = AppState.shared

从SwiftUI视图访问：

struct ContentView: View {
    @EnvironmentObject var appState: AppState

从NSViewRepresentable / UIViewRepresentable协调器类访问：

class Coordinator: NSObject, MTKViewDelegate {
...  
        func draw(in view: MTKView) {
            ...
            context.render((AppState.shared.rawImage ?? AppState.shared.rawImageOriginal)!,
                to: drawable.texture,
                commandBuffer: commandBuffer,
                bounds: AppState.shared.rawImageOriginal!.extent,
                colorSpace: colorSpace)
    }
...