Listen whatsapp messages on car speaker via bluetooth

Hi

I would like to listen whatsapp messages on my car audio speaker via bluetooth simply using "hey Siri" (or the voice button on my steering wheel); I've tried :

Notification --> Whatsapp --> Show Previews --> Always

Siri&Search --> Allow Siri When Locked

Bluetooth - > "Bluetooth of my Car" --> Show Notification

However sometimes "Hey Siri" works perfectly, sometimes Siri tells me that there is no new messages (even if there are ), sometimes it's ask to unlock the phone...

I've tried both asking "New Whatsapp Messages" and "New Notifications"...

Any help ?

I have CarPlay, but I don't like to use it...