We don't have Android Auto Wireless capabilities (Unlike Apple CarPlay that does), you'll need a cable. Have you been to the Google Playstore on your phone and installed AndroidAuto? Your phone needs the additional software for your Q3's systems to connect to.
Android11 supports Wireless AndroidAuto but the Audi's media platform (certainly the MIB2+ version that you and I have) doesn't. The very latest version which appeared for the 2021 model year, MIB3, may have additional capabilities we are yet to discover.