Tile loading in World Composition is made asynchronously only in cooked mode (see 4.18.2 engine code of FAsyncLoadingThread::ShouldBeMultithreaded()). Potentially other functionalties are impacted, maybe async loading in general, I am not sure where FAsyncLoadingThread is being used else. This makes things impractical during development like when working under the UE Editor. Can the async behavior be enabled only based on the project settings flag regardless of whether the game is cooked?
I made the below posts about the topic but I don’t think they reached UE developers: