Operating systems are incredibly complex pieces of software, so it might not come as a surprise that despite multiple beta releases, some bugs crept into the final version of Android 11. The update apparently caused issues with Android Auto resulting in some drivers not being able to play music or read notifications.
There have been many reports on social media of issues with Android Auto after updating to Android 1
One possible workaround has been discovered by Reddit users Yewtsan and mtb_junkie, which is to disable scanning of Bluetooth devices in the phone settings. While Google hasn’t yet promised a solution to all of the above issues, the Android Auto v5.6 update has already been released with a fix for the missing calendar app.