Sure you can, you just have to manage them separately.
Separately, the spawn-actor call does allow you to specify a specific Level to spawn in. Presumably you can, like, ray-trace to the closest support for the object you spawn, and spawn the object in the same world.
That being said, you won’t be editing that world on disk, so I’d expect that when it unloads, it’s gone.
Hence, why you should listen for world load/unload events, and have your own grid of “user spawned actors” that you can manage. Perhaps the simplest would be a savegame instance per world partition grid cell or something like that.