World Composition questions

Hello, i’m planning to make an open world multiplayer game but i have some issues with the map setup.

I read that I should use World Composition to free up memory in a big world (16km²), but I’m confused with some points.

  1. Should I use World Composition, knowing that UE5 is coming soon, and features Nanite?

  2. If I should use World Comp, is it possible to spawn actors inside a sublevel (eg. Building System)? (So they can Show/Hide based on the Streaming Distance)

Hope you can help me !