I’m not 100% sure but I don’t think you can reference an entity as an editable in a device. As an alternative you could grab the Simulation Entity (root of all entities) in the device then search for the entity you want.
Use this API to grab the Simulation Entity in your device:
@experimental
# Returns the simulation entity at the root of the experience this `creative_object` is operating within.
# * The simulation entity is the rootmost entity in an experience.
# * Fails if this `creative_object` is not operating in a context with a valid SimulationEntity.
(CreativeObject:creative_object).(/Fortnite.com/Devices:)GetSimulationEntity<native><public>()<transacts><decides>:entity
Then you can search for your entity with a tag:
@experimental
@available {MinUploadedAtFNVersion := 2930}
# Finds all descendant entities including `InEntity` with `Tag` present in their `tag_component`.
# When querying from the simulation entity, the simulation entity itself is not included in the results.
# The order of the returned entities is unspecified and subject to change.
(InEntity:entity).FindDescendantEntitiesWithTag<native><public>(Tag:tag)<transacts>:generator(entity)
Or if you don’t want to use a tag, you can add a custom component to those entities and search by component:
@experimental
@available {MinUploadedAtFNVersion := 3200}
# Finds all descendant entities including `InEntity` containing a component of type `component_type`.
# The order of the returned entities is unspecified and subject to change.
(InEntity:entity).FindDescendantEntitiesWithComponent<native><public>(component_type:castable_subtype(component))<transacts>:generator(entity)
There are a couple other ways to search for entities too. Just search for FindDescendant inside of Verse.digest.verse