Custom variable in "device"?

[joq3]

I was wondering if there is some functionality in Home Assistant that allows me to enter the name of a variable under device: variable_name
This would allow me to create a helper (for example a dropdown selection).
The goal is for the selected item in the helper to be choosen as the device.

  cards:
    - type: 'custom:spotify-card'
      device: <optional name of a device to pre-select>

I would like to make a custom UI for this, that's why I am looking for a way to use a variable for the device.