If you’re really really sure you want to spawn actors in a construction script (you’ll have to manage their lifetime yourself), you can put this helper function into a blueprint function library:
UFUNCTION(BlueprintCallable, Category="Actor|Utilities", meta=(Keywords="spawn actor"))
AActor* SpawnActor(UWorld* World, UClass* Class)
{
FActorSpawnParameters fp;
fp.bAllowDuringConstructionScript = true;
return World->SpawnActor<AActor>(Class, fp);
}