Question How to tackle loading assets for a Map Editor?

Hello!

Id love to hear some ideas on how to tackle asset management. we are making a map editor inside unity, so there's a heck ton of assets to load. (more or less 300 prefabs, not counting textures, models,etc)

Right now, we have scriptable objects in the folder resources which references the prefabs localized in other folder non-resource. But since the scriptables references the assets, all of them are loaded when the scene is loaded.That's ok since we have a loading screen beforehand.
The issue is that the amount of assets is so big that Unity closes itself without any warning when building!

We've tried using Addressables, it builds perfectly! Following the same idea from before, we are loading all of the assets when the scene opens. But takes a really long time (like 5 minutes) to load them. And it's not that reliable.. (probably our code tho)

Has anyone made an map editor inside unity? If so, how the assets were managed? Were they loaded when the user pushed the "spawn button" or loaded beforehanded?

We are using Unity 2020.3.17f1.