@MartinFin
The Spotify integration makes a call to an underlying library which in turn makes a call to the Spotify Web API Get Available Devices endpoint to retrieve the source list (or device list as it’s known by in the Spotify Web API). The link above allows you to use the Spotify Developer “Try It” functionality to display the devices that Spotify knows about for the account. You can logout / login to that link with your daughters account (or use Chrome browser incognito mode to view both in new tabs / windows).
The results will look something like this, with your response devices
collection containing different entries for YOUR environment:
That fact that your daughter’s Spotify player is only showing 1 device, while your Spotify player shows multiple devices, indicate that she used her player recently and the device is still “logged on” to her account. Your Spotify player shows all of the other devices since you have them registered (by default) to YOUR Spotify account.
With that said, let me offer you an alternative to the HA Spotify integration …
Check out the SpotifyPlus Integration; it can do everything that the HA Spotify integration can do, supports Spotify Connect enabled devices (Bose, Sonos, Chromecast, Amazon Alexa, Denon, JBL, and more), and provides 95+ custom services that can be used in HA automations and scripts.
The SpotifyPlus integration will also list available devices that are on your network, but may be in a “sleep” state. In other words, it not only contains the Spotify Web API Get Available Devices endpoint results, but also contains any devices advertised by the ChromeCast zeroconf protocol and Spotify Connect zerconf protocol.
There is also a SpotifyPlus Card user-interface that allows you to control the player, manage your Spotify favorites, as well as search the Spotify catalog. You have to install the SpotifyPlus integration first though, and get it configured before you can use the SpotifyPlus Card.
Both are easily installed via HACS.
Hope it helps!