Spawn Actor to the world before level editor showup

Hello, I was trying to spawn new actors into the map but before the Unreal Editor fully opens, so I don’t have to drag these actors from blueprint to the level editor one by one.
Here is what I tried:
I was placing the spawning code in the constructor, but inside the constructor, GetWorld() function will return null, thus it won’t work. Then I tried to move the code to BeginPlay function, but now I can only see the player instance after I hit the Play button. Is there a way to spawn the actor into the world in runtime but before Unreal Editor fully loaded? following is the code I used.

ActorSpawnParams.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;
ActorSpawnParams.Instigator = this;
AObstacleActor* StaticMeshActor = GetWorld()->SpawnActor<AObstacleActor>(StaticMeshActorClass, FVector(500.0f,76.0f,205.0f),FRotator(0,0,0),ActorSpawnParams);