A UILabel-based SwiftUI view which auto-expands to the width of the container, and only expand to render the full height of the label.

AutoHeightLabelView.swift

struct AutoHeightLabelView: View {
    var attributedString: NSAttributedString

    var body: some View {
        HorizontalGeometryReader { width in
            UILabelView(
                attributedString: attributedString,
                preferredMaxLayoutWidth: width
            )
        }
    }
}

fileprivate struct UILabelView: UIViewRepresentable {
    var attributedString: NSAttributedString
    var preferredMaxLayoutWidth: CGFloat = .greatestFiniteMagnitude

    public func makeUIView(context: UIViewRepresentableContext<UILabelView>) -> UILabel {
        let label = UILabel(frame: .zero)
        label.numberOfLines = 0
        label.setContentHuggingPriority(.required, for: .vertical)
        label.setContentCompressionResistancePriority(.required, for: .vertical)
        label.setContentHuggingPriority(.defaultLow, for: .horizontal)
        label.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)

        updateUIView(label, context: context)
        return label
    }

    public func updateUIView(_ label: UILabel, context: UIViewRepresentableContext<UILabelView>) {
        label.attributedText = attributedString
        label.preferredMaxLayoutWidth = preferredMaxLayoutWidth
    }
}

fileprivate struct HorizontalGeometryReader<Content: View> : View {
    var content: (CGFloat) -> Content
    @State private var width: CGFloat = 0

    public init(@ViewBuilder content: @escaping (CGFloat) -> Content) {
        self.content = content
    }

    public var body: some View {
        content(width)
            .frame(minWidth: 0, maxWidth: .infinity)
            .background(
                GeometryReader { geometry in
                    Color.clear
                        .preference(key: WidthPreferenceKey.self, value: geometry.size.width)
                }
            )
            .onPreferenceChange(WidthPreferenceKey.self) { width in
                self.width = width
            }
    }
}

fileprivate struct WidthPreferenceKey: PreferenceKey, Equatable {
    static var defaultValue: CGFloat = 0

    /// An empty reduce implementation takes the first value
    static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
    }
}

Hey @mrackwitz I found this very useful, thank you!

I was having issues on switching my tab bar and returning and also after changing dynamic type size during runtime, as the height was reset somehow.

I added a unique ID to the geometry reader to fix the issue as follows:

        .id(
            // Fixes height issues on tab change
            // Fixes height issues on dynamic type change
            UUID().uuidString
        )