Got fixed! TimerType and TimerAction can not both conform to AppEnum and AppEntity protocols. Remove the AppEntity, it will work.

Here is some code snippets: ... ForEach(pngs) { row in TableRow(row) .itemProvider { row.targetURL.flatMap(NSItemProvider.init(contentsOf:)) } } ... .onDrop(of: [.png], isTargeted: $isDropTarget) { providers in files.removeAll() providers.forEach { provider in _ = provider.loadFileRepresentation(for: .png, openInPlace: true) { url, _, _ in Task { @MainActor in url.map { files.append(.init(url: $0)) } } } } return true } ...