Just a heads-up as many users in that thread are reporting Android Auto issues with their Pixel 8 and 8 Pro phones, and the response by the Android Auto team there is to file a bug report.
Do you also encounter issues with Android Auto with the Pixel 8/8 Pro?
I paired my P8P to my car last week and was able to use it. Today, it doesn’t even appear to try to connect. My other vehicle, which has the motorola AA dongle in it, works a-ok still. My P7 no longer connects to the first car either, so, at least for me, it’s not just pixel 8 specific.