How to stream an iMovie on a Mac to a smart TV

I have an iMovie I want to stream from my MacBook to my LG TV (without Apple TV). After I select Screen Mirroring on the Mac and select the LG TV, it does mirror the Mac and I can play the movie; however, there is no sound.

Alternatively, if I go into Mac System Settings and select Bluetooth, I can connect to the TV and it will play sounds from the Mac (but it stops the screen mirroring).

What is the right way to do this? Should I be using screen mirroring or AirPlay? Can I even use AirPlay to connect my Mac to a TV that does not have Apple TV?

Note: I also have a Sony TV with Apple TV attached. I can successfully use screen mirroring to play the movie with video and sound. When I connect screen sharing, I can connect either to the TV or the Apple TV. They both work.