Sparkle + SwiftUI

Sparkle.swift

lass AppUpdateHandler: ObservableObject {
    #if SPARKLE
    private let delegateHandler = SparkleDelegateHandler()
    let sparkle: SPUStandardUpdaterController

    init() {
        // Setup sparkle updater
        // https://docs.microsoft.com/en-us/appcenter/distribution/sparkleupdates
        // https://rambo.codes/posts/2021-01-08-distributing-mac-apps-outside-the-app-store
        sparkle = SPUStandardUpdaterController(updaterDelegate: delegateHandler, userDriverDelegate: delegateHandler)
    }

    func checkForUpdates() {
        // https://sparkle-project.org/documentation/
        sparkle.checkForUpdates(delegateHandler)
    }

    private class SparkleDelegateHandler: NSObject, SPUUpdaterDelegate, SPUStandardUserDriverDelegate {
        func feedURLString(for updater: SPUUpdater) -> String? {
            "https://api.appcenter.ms/..." // or whatever you use
        }
    }
    #endif
}

typo: *class

Question: Do we need to build a macOS plugin for Sparkle like this example?

Yes, you need to follow the 2.0 integration guide.