Custom TabBar implementation for UIKitPlus. Not beautiful cause not wrapped, just sources. But it works well.

UIKitPlus-TabBarImplementation.swift

import UIKitPlus

class MainViewController: ViewController {
    override var statusBarStyle: StatusBarStyle {
        if let controller = controllers[current]?.protocolController {
            if let controller = controller as? ViewController {
                return controller.statusBarStyle
            }
            return .from(controller.preferredStatusBarStyle)
        }
        return .default
    }
    
    lazy var home = WrappedViewControllerView.home(self)
    lazy var statistics = WrappedViewControllerView.statistics(self)
    lazy var trophy = WrappedViewControllerView.trophy(self)
    lazy var marketplace = WrappedViewControllerView.marketplace(self)
    lazy var balance = WrappedViewControllerView.balance(self)
    
    typealias Controllers = [HomeTab: WrappedViewControllerable]
    lazy var controllers: Controllers = [.home: home, .statistics: statistics, .trophy: trophy, .marketplace: marketplace, .balance: balance]
    
    @UState var current: HomeTab = .home
    
    lazy var bottomBar = BottomTabBar($current)
    
    var presentingGoalEndedView = false
    
    override func buildUI() {
        super.buildUI()
        view.backgroundColor = 0xf5f6f8.color
        body {
            home
            statistics
            trophy
            marketplace
            balance
            bottomBar
        }
        switchToController(current)
        $current.listen { old, new in
            guard old != new else { return }
            self.switchToController(new)
        }
    }
    
    func switchToController(_ new: HomeTab) {
        controllers.forEach { $0.value.hidden($0.key != new) }
        navigationController?.setNeedsStatusBarAppearanceUpdate()
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        (navigationController as? NavigationController<MainViewController>)?.isSwipeBackEnabled = true
    }
}

#if canImport(SwiftUI) && DEBUG
import SwiftUI
@available(iOS 13.0, *)
struct MainViewController_Preview: PreviewProvider, DeclarativePreview {
    static var preview: Preview {
        Preview {
            MainViewController()
        }
        .colorScheme(.dark)
        .device(.iPhoneX)
        .language(.en)
    }
}
#endif

// MARK - AppDelegate

extension AppDelegate {
    static var shared: AppDelegate {
        UIApplication.shared.delegate as! AppDelegate
    }
}

extension AppDelegate {
    var safeInsets: UIEdgeInsets {
        window?.safeInsets ?? .zero
    }
}

// MARK: - Tab images

extension UIImage {
    static var homeTab: UIImage? { UIImage(named: "tabBarHome") }
    static var statisticsTab: UIImage? { UIImage(named: "tabBarStatistics") }
    static var trophyTab: UIImage? { UIImage(named: "tabBarTrophy") }
    static var marketplaceTab: UIImage? { UIImage(named: "tabBarMarketplace") }
    static var balanceTab: UIImage? { UIImage(named: "tabBarBalance") }
}

// MARK: - Tab titles

extension String {
    static var homeTitle: String { String(.en("___"), .ru("___")) }
    static var statisticsTitle: String { String(.en("___"), .ru("___")) }
    static var trophyTitle: String { String(.en("___"), .ru("___")) }
    static var marketplaceTitle: String { String(.en("___"), .ru("___")) }
    static var balanceTitle: String { String(.en("___"), .ru("___")) }
}

// MARK: - Tab colors

extension UIColor {
    static var tabBarActive = 0x3EC900.color
    static var tabBarInactive = UIColor.lightGray
}

// MARK: - Tab types

enum HomeTab {
    case home, statistics, trophy, marketplace, balance
    var title: String {
        switch self {
        case .home: return .homeTitle
        case .statistics: return .statisticsTitle
        case .trophy: return .trophyTitle
        case .marketplace: return .marketplaceTitle
        case .balance: return .balanceTitle
        }
    }
    var icon: UIImage? {
        switch self {
        case .home: return .homeTab
        case .statistics: return .statisticsTab
        case .trophy: return .trophyTab
        case .marketplace: return .marketplaceTab
        case .balance: return .balanceTab
        }
    }
}

// MARK: TabBar view

class BottomTabBar: UView {
    var state: UState<HomeTab>
    
    init (_ state: UState<HomeTab>) {
        self.state = state
        super.init(frame: .zero)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func buildView() {
        super.buildView()
        background(.white)
        border(.top, 1, 0xF3F3F3)
        height(84 + AppDelegate.shared.safeInsets.bottom)
        edgesToSuperview(leading: 0, trailing: 0, bottom: 0)
        body {
            UHStack {
                BottomTabBarButton(.home, state: state)
                BottomTabBarButton(.statistics, state: state)
                BottomTabBarButton(.trophy, state: state)
                BottomTabBarButton(.marketplace, state: state)
                BottomTabBarButton(.balance, state: state)
            }
            .centerXInSuperview()
            .topToSuperview(16)
            .height(50)
            .distribution(.equalSpacing)
        }
    }
}

// MARK: TabBar item view

class BottomTabBarButton: UView {
    let image: UIImage?
    let title: String
    let type: HomeTab
    let state: UState<HomeTab>
    
    lazy var imageView = Image(image)
    lazy var titleLabel = Text(title)
    
    init(_ type: HomeTab, state: UState<HomeTab>) {
        self.title = type.title
        self.image = type.icon
        self.type = type
        self.state = state
        super.init(frame: .zero)
        updateSelection()
        state.listen(updateSelection)
        onTapGesture(tapAction)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func buildView() {
        super.buildView()
        body {
            UVStack {
                imageView
                    .mode(.scaleAspectFit)
                    .size(25)
                    .topToSuperview()
                    .centerXInSuperview()
                titleLabel
                    .top(to: .bottom, of: imageView, 4)
                    .edgesToSuperview(leading: 0, trailing: 0, bottom: 0)
                    .alignment(.center)
                    .font(.helveticaNeueMedium, 12)
            }.edgesToSuperview().width(75 !! .iPhone6(70) !! .iPhone5(70))
        }
    }
    
    func updateSelection() {
        imageView.tint(state.wrappedValue == type ? .tabBarActive : .tabBarInactive)
        titleLabel.color(state.wrappedValue == type ? .tabBarActive : .tabBarInactive)
    }
    
    func tapAction() {
        guard state.wrappedValue != type else { return }
        ImpactFeedback.selected()
        state.wrappedValue = type
    }
}

// MARK: - Helper extensions

extension WrappedViewControllerView {
    static func home(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController1>> {
        let r = improve(_home(parent)).bottom(to: .top, of: parent.bottomBar, -20)
        r.inner.style(.transparent).hideNavigationBar()
        return r
    }
    
    static func statistics(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController2>> {
        let r = improve(_statistics(parent)).bottom(to: .top, of: parent.bottomBar, -20)
        r.inner.style(.transparent).hideNavigationBar()
        return r
    }
    
    static func trophy(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController3>> {
        let r = improve(_trophy(parent)).bottom(to: .top, of: parent.bottomBar, -20)
        r.inner.style(.transparent).hideNavigationBar()
        return r
    }
    
    static func marketplace(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController4>> {
        let r = improve(_marketplace(parent)).bottom(to: .top, of: parent.bottomBar, -20)
        r.inner.style(.transparent).hideNavigationBar()
        return r
    }
    
    static func balance(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController5>> {
        let r = improve(_balance(parent)).bottom(to: .top, of: parent.bottomBar, -20)
        r.inner.style(.transparent).hideNavigationBar()
        return r
    }
    
    static func improve<V>(_ v: V) -> V {
        (v as? UView)?.edgesToSuperview(top: 0, leading: 0, trailing: 0)
        return v
    }
}

// MARK: Tricky implementation to make generics work

extension WrappedViewControllerView {
    fileprivate static func _home(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController1>> {
        .init(.init(.init(parent)), parent: parent)
    }
    
    fileprivate static func _statistics(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController2>> {
        .init(.init(.init(parent)), parent: parent)
    }
    
    fileprivate static func _trophy(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController3>> {
        .init(.init(.init(parent)), parent: parent)
    }
    
    fileprivate static func _marketplace(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController4>> {
        .init(.init(.init(parent)), parent: parent)
    }
    
    fileprivate static func _balance(_ parent: MainViewController) -> WrappedViewControllerView<NavigationController<ViewController5>> {
        .init(.init(.init(parent)), parent: parent)
    }
}

// MARK: - Tab Controllers

class MainSubController: ViewController {
    let mainViewController: MainViewController
    
    init (_ mainViewController: MainViewController) {
        self.mainViewController = mainViewController
        super.init()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class ViewController1: MainSubController {}
class ViewController2: MainSubController {}
class ViewController3: MainSubController {}
class ViewController4: MainSubController {}
class ViewController5: MainSubController {}