Hello there @auroraxfoafoa!
What you are encountering here is two systems clashing with each other.
If World Partition is enabled on your map, your streaming nodes won’t respond, since it only listens to data layers. Meaning, your levels are not loading/unloading due WP shutting down level streaming. It comes down to choosing one approach, the one that suits bests for your project:
If you want the level streaming workflow you already have in place, disable WP, and eep your sublevels inside a persistent level. On the other hand, if you would rather work with WP, disable your current setup, and re-organize your content into data layers.
As for choosing which method is better for your project, please refer to a similar scenario in the thread below, where both features are discussed. You can also check the related UE documentation, and the world building map, an excellent resource for open worlds: