When is custom gamemode spawned?

Hi community,
OnConstruction event in my gamemode is called after BeginPlay event in my actors on scene.
Why has gamemode this behaviour ?
How can I spawn actors on scene before OnConstruction event in my gamemode?

Or:
I need to spawn actor which have to be spawned before any others actors. Is there any way how to do it except using gamemode event OnConstruction?

Thanks a lot.

It seems that GameMode is spawned after BeginPlay in actors is called.

My solution was use TActorIterator where I access actors on scene. It’s quite fast.

void AMyGameMode::RegisterControlObjects()
{
	//EngineUtils.h
	for (TActorIterator<AControlObject> ActorItr(GetWorld()); ActorItr; ++ActorItr)
	{
          //some code
	}
} 

I’m still interested in spawning order.
Actor is spawned and BeginPlay on actor is called. After that is spawned GameMode. It’s confusing for me.

Is there any component which is spawned before absolutely first ?