Thanks for reaching out. You can display your entire computer screen using Chrome on Mac, Windows, and Chrome OS. However, to play the audio on your TV, use a Windows computer. You can see the information here. Instead of casting your MacBook screen, please try to cast a Tab and check if the same issue will persist.
Just one quick final check in here since activity has slowed down. We haven't heard from you in a while so we'll be locking this thread if there is no update after 24 hours. If you have any new questions, updates or just a discussion topic, feel free to start a new thread in the Community.