Thank you for your help. I did not even think about BlueprintAsyncActionBase. I’ll surely look into this!
Your utility looks interesting, I appreciate showing it.
The initial plan was to spawn the rooms during a loading screen. The issue is that if I would want to make a world with 100 or more rooms, the loading time would increase linearly. This is not such a problem for a player with a fast CPU, but I would say that dividing the work into async would speed up the loading process. Instead of spawning 1 room synchronously, it would drastically help to reduce the loading time by spawning 4 or 8 rooms at a time.
If there is no way of actually spawning actors in async, I should probably divide the work during the gameplay (spawning some of the rooms in-game).