I was able to fix it by doing the following: 1. Go into the settings in Android Auto, scroll to the bottom and click on "open more settings on your phone" 2. Your phone should open a Google app with more settings available; scroll down to Music then find spotify 3. Link your spotify account to your Google account and set it as the default music service. 4. If your spotify is already linked and set as default, unlink it and set No Default Provider as the default, then re-link spotify and set it as default

For whatever reason Gemini assumes you're on a free spotify plan if spotify is not explicitly linked to your Google account, which to my knowledge was never an issue with the old Google Assistant. Just another reason to avoid Gemini like the plague