This app was mentioned in 3 comments, with an average of 1.67 upvotes
No firmware upgrade for my 2016 Accord is available, but this app did fix it for many others and also worked for me.
https://play.google.com/store/apps/details?id=com.android_rsap.irmctest
Regardless, backwards compatibility shouldn't be an issue with something like Bluetooth. I could understand if I'm driving a 1992 car, but my car is less than a year old. Google has tried to blame it on the car companies, but considering all other phones work fine, that's just them deflecting. It's their problem. I'd also be less frustrated if they'd acknowledge the issue, but despite almost 2000 posts in threads on their forums, they've ignored it.
But that app developer is going to make a fortune. :-)
Try the app "Bluetooth Phonebook" . The trial allows you to test if it works.
https://play.google.com/store/apps/details?id=com.android_rsap.irmctest
I don't know if it solves your problem, but I wasn't able to use ANY contacts on my VW Golf MK7, and this app fixed everything for me.
Idk if it fixes the problem but I have 16 Honda accord and I downloaded this app https://play.google.com/store/apps/details?id=com.android_rsap.irmctest and it fixed all my problems.