It seems that -childForStatusBarStyle: isn’t called on a UIViewController that is presented from a SwiftUI view using UIViewControllerRepresentable. Or am I doing something wrong? I came up with this *ugly* workaround that swizzles -childForStatusBarStyle: to return an associated object when present and uses the default implementation as fallback.

childForStatusBarStyle.swift

// We'll store a UIViewController as an associated object and don't want to store a strong reference to it.
private final class WeakBoxedValue<T: AnyObject>: NSObject {
    private(set) weak var value: T?

    init(_ value: T?) {
        self.value = value
    }
}

// Use associated objects to a UIViewController that should determine the status bar appearance.
private var forcedChildForStatusBarStyleKey: Void?
extension UIViewController {
    var sbs_forcedChildForStatusBarStyle: UIViewController? {
        get {
            let boxedValue = objc_getAssociatedObject(self, &forcedChildForStatusBarStyleKey) as? WeakBoxedValue<UIViewController>
            return boxedValue?.value
        }
        set {
            if let newValue = newValue {
                objc_setAssociatedObject(self, &forcedChildForStatusBarStyleKey, WeakBoxedValue(newValue), .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            } else {
                objc_setAssociatedObject(self, &forcedChildForStatusBarStyleKey, nil, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            }
        }
    }
}

// Swizzle UIViewController to use our sbs_forcedChildForStatusBarStyle when available.
extension UIViewController {
    static let classInit: Void = {
        if let originalMethod = class_getInstanceMethod(UIViewController.self, #selector(getter: childForStatusBarStyle)),
           let swizzledMethod = class_getInstanceMethod(UIViewController.self, #selector(getter: sbs_childForStatusBarStyle)) {
            method_exchangeImplementations(originalMethod, swizzledMethod)
        }
    }()

    @objc var sbs_childForStatusBarStyle: UIViewController? {
        return sbs_forcedChildForStatusBarStyle ?? self.sbs_childForStatusBarStyle
    }
}

// This view is presented modally from another SwiftUI view using fullScreenCover(isPresented:)
struct DemoView: UIViewControllerRepresentable {
    func makeUIViewController(context: Context) -> some UIViewController {
        return DemoViewController()
    }

    func updateUIViewController(_ uiViewController: UIViewControllerType, context: Context) {}
}

// This is the view controller being presented modally. Sets itself as being the child 
// that determine the status bar appearance on its parent UIHostingController.
final class DemoViewController: UIViewController {
    override func willMove(toParent parent: UIViewController?) {
        super.willMove(toParent: parent)
        // When the UIViewController is presented modally from a SwiftUI, it will be
        // wrapped in a PresentationHostingController<AnyView>. We detect that and
        // set the UIViewController to determine the status bar appearance. This is not good 😬
        if let parent = parent, String(describing: type(of: parent)).hasPrefix("PresentationHostingController") {
            parent.modalPresentationCapturesStatusBarAppearance = true
            parent.sbs_forcedChildForStatusBarStyle = self
            parent.setNeedsStatusBarAppearanceUpdate()
        }
    }
}