There is one way to deal with this. I also was looking for a way to have my structures in playsets to be able to add them from the Content Browser. You create a Level, your models and build your scene, say a house or something. Then, under World Settings, toggle the IsPlayset checkbox and choose Prefab under Category ( Does not matter what you choose here ). There a few options in there, like setting thumbnails, etc. Save the Level. Open your project folder in Explorer, under the _INT folder you will see the level file creates a uasset file. Copy this and paste it in any of your folders in the project. Go back to Unreal and in the Content Browser, navigate to the copied file . Double click the file and in the Details panel, under Source Map, select the Level file you made your prefab in. Save. You can now drag and drop the file from the Content Browser to your map. For more details there is a tutorial video on YouTube about this same thing.
Good luck!