you must turn on Gemini Apps Activity in your Google account settings. Further, the Spotify extension works only when Gemini's language is set to English. How to enable and use Gemini's Spotify ...

you can now use natural language prompts to change aspects of your smart devices. In the Gemini app, you can say or type ...

You won’t be able to use the Spotify extension inside Google Messages, the Gemini web app, or the Gemini app on iOS, and it only works while Gemini’s language is set to English to start.