MarqueeLabel Please be fully aware that these use Private APIs.

MarqueeLabel-Minimal.swift

let label = UILabel()
label.text = "Swift is a modern, intuitive programming language crafted for all Apple platforms."
label.setValue(true, forKey: "marqueeEnabled")
label.setValue(true, forKey: "marqueeRunning")
label.setValue(0, forKey: "marqueeRepeatCount")

MarqueeLabel.swift

//
//  MarqueeLabel.swift
//  PrivateAPISample
//  
//  Created by Chronos2500 on 2025/05/13.
//

import SwiftUI

fileprivate let text = """
Swift is a modern, intuitive programming language crafted for all Apple platforms. 
"""

struct MarqueeLabelView: View {
    var body: some View {
        MarqueeLabel(
            text,
            font: .preferredFont(forTextStyle: .title1)
        )
    }
}

struct MarqueeLabel: UIViewRepresentable {
    var text: String
    var repeatCount: Int
    var font: UIFont
    var textColor: UIColor

    init(
        _ text: String,
        repeatCount: Int = 0,
        font: UIFont = .preferredFont(forTextStyle: .body),
        textColor: UIColor = .label
    ) {
        self.text = text
        self.repeatCount = repeatCount
        self.font = font
        self.textColor = textColor
    }

    func makeUIView(context: Context) -> UILabel {
        let label = UILabel()
        label.text = text
        label.textAlignment = .natural
        label.font = font
        label.textColor = textColor
        label.backgroundColor = .clear
        label.numberOfLines = 1
        label.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        label.setContentHuggingPriority(.defaultLow, for: .horizontal)
        label.setContentHuggingPriority(.required, for: .vertical)
        label.setContentCompressionResistancePriority(.required, for: .vertical)
        label.adjustsFontForContentSizeCategory = true
        label.setValue(true, forKey: "marqueeEnabled")
        label.setValue(true, forKey: "marqueeRunning")
        label.setValue(repeatCount, forKey: "marqueeRepeatCount")
        label.setValue(40, forKey: "marqueeLoopPadding")
        label.setValue(true, forKey: "marqueeUpdatable")
        return label
    }
    func updateUIView(_ uiView: UILabel, context: Context) {
    }
}

#Preview {
    MarqueeLabelView()
}