Making TabView not translucent on SwiftUI produces a new view on top

This is the correct way to do it.

It works with SwiftUI too as the TabView and NavigationView are actually UIHostedController for the legacy UITabBarController and UINavigationController.

Edit: Just watched Modernizing Your UI for iOS 13 This is the way to do it :

let appearance = UINavigationBarAppearance()
appearance.configureWithOpaqueBackground()
appearance.titleTextAttributes = [.foregroundColor: UIColor.white]
appearance.largeTitleTextAttributes = [.foregroundColor: UIColor  .white]

Then set the appearance on the various type of appearance.

navigationBar.standardAppearance = appearance
navigationBar.compactAppearance = appearance
navigationBar.scrollEdgeAppearance = appearance

Reference: https://developer.apple.com/videos/play/wwdc2019/224/

2nd Edit: Need a figure out a clean way to get to the UINavigationController from a SwiftUI view.

In the meantime, this will help:

extension UINavigationController {
    override open func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        let appearance = UINavigationBarAppearance()
        appearance.configureWithOpaqueBackground()
        navigationBar.standardAppearance = appearance
        navigationBar.compactAppearance = appearance
        navigationBar.scrollEdgeAppearance = appearance
    }
}

extension UITabBarController {
    override open func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        let appearance = UITabBarAppearance()
        appearance.configureWithOpaqueBackground()
        tabBar.standardAppearance = appearance
    }
}

You can set a tabbar color with this code. Write this code in SceneDelegate

UITabBar.appearance().shadowImage = UIImage()
UITabBar.appearance().backgroundImage = UIImage()
UITabBar.appearance().isTranslucent = true
UITabBar.appearance().backgroundColor = .black

In TabBar Background you can set any other color instead of black. Its working perfectly fine.

ContentView:

TabView(selection: $selection) {
        Text("1st View")
            .tabItem {
                Image(systemName: "house.fill")
                    .font(.title)
            }
            .tag(0)

        Text("Second View")
            .font(.title)
            .tabItem {
                Image(systemName: "bell.fill")
                    .font(.title)
            }
            .tag(1)
    }
        .edgesIgnoringSafeArea(.top)