Some clarifications needed about level streaming

Disclaimer: My background is in Unity

My needs: a loading screen and being able to load and unload different and discrete levels.

How do I do it?

From what I have read in the docs and tutorials I would need to create an “empty” persistent level for the whole game and then stream in and out the levels. The loading screen may be part of the persistent level or streamed in and out when needed.

The problem I have with this approach is that when I add a level in the Levels window all the levels in the editor are loaded even if their streaming method is set to Blueprint. Why?

I’m going to have around 20 levels with high quality assets and I would prefer to avoid any potential issue.