If the previous owner of your car has not removed their profiles and connected phones, a factory reset of the car is needed. You can do this yourself via the car's centre display or ask the previous owner to do it via the Volvo Cars/Volvo EX30 app.
If the centre display's response is slow, it might help to restart the display. A restart may also fix the problem if you are experiencing issues with e.g. Bluetooth, navigation or connectivity.
Google has a support site for the Google apps and services that are built into your car. You can also find a complete list of Google apps available to your region.
If you are experiencing issues with Google services in your car, you can send feedback and detailed information directly from the centre display.