With iOS 18:
Drivers can now listen to Spatial Audio songs and albums available in Apple Music and third-party apps while connected to CarPlay. Vehicles with multichannel audio capabilities can enable an immersive sound experience. Spatial Audio with support for Dolby Atmos can also be implemented in compatible vehicles.
https://www.apple.com/ios/ios-18/pdf/iOS_18_All_New_Features_Sept_2024.pdf
Of course the vehicle Head Unit must support Dolby Atmos. Dolby also confirms support for CarPlay:
https://professional.dolby.com/music/dolby-atmos-for-cars/carplay-support-for-dolby-atmos/#gref
There are old documents on the internet that have conflicting information and also some users have no idea that their vehicle has to support it, so they make the claim that it is not available.