ButtonViewAnyViewExtension.swift

// Put in top level file scope
extension View {
    func eraseToAnyView() -> AnyView {
        AnyView(self)
    }
}

private func buildComplexButton() -> some View {
    if someConditional {
        return Button(action: { /* do something */ }) {
            Text("1")
        }.eraseToAnyView()
    } else {
        return Button(action: { /* do something else */ }) {
            Image(systemName: "faceid")
        }.eraseToAnyView()
    }
}