Scala, cake pattern and mixins. How to avoid many parameters in "injected" class

Question

While building a new Playframework app I am trying to use the cake pattern.

My first understanding was to mix custom traits into the controllers and pass those provided by Play as parameter:

trait MyComponents {
   def actorSystem: ActorSystemClassic
   lazy val service  = new MyService(actorSystem)
}

class MyController(
  controllerComponents: ControllerComponents, 
  override val actorSystem: ActorSystemClassic) with MyComponents { 
  

  // ...
  // Use `service` from MyComponents
}

class MyApp extends BuiltInComponentsFromContext(context) {
  val controller = new MyController(
        controllerComponents,     // <- Provided by BuiltInComponentsFromContext
  )
}

That worked fine until I had to test MyController and tried to mock the service.

To mock the service I should be able to work with a stub of MyComponents that will provide the mock. To provide that stub I have to pass it as constructor parameter.

class MyController(
  controllerComponents: ControllerComponents,
  myComponents: MyComponents,
  override val actorSystem: ActorSystemClassic) {

  // ...
  // Use `myComponents.service`
}

Of course my controller is more complex than that and he need more than one component to work. My fear is to end with a constructor that will become hardly manageable, with a lot of parameters.

To limit the number of parameters, one idea would be to mix all of the components in one. However I am not able to mix the instance on ControllerComponents provided by the super class BuiltInComponentsFromContext with MyComponents:

class MyController(components: MyComponents with ControllerComponents)

class MyApp extends BuiltInComponentsFromContext(context) {
  val controller = new MyController(
     new MyComponents with /*instance of controllerComponents provided by BuiltInComponentsFromContext*/
  )
}

I do not want to pass the controllerComponents to MyComponents because that class provide business services, she don not care about controller components.

Can you help me to implement a real life application with the cake pattern ?