Amazon has been focusing more and more on audio quality lately, so using Echo devices as a wireless audio solution for your TV seems like a smart move. Customers with the current generation of Echo and Echo Plus can stream Dolby sound wirelessly, and customers with Echo Studio can stream Dolby Atmos-quality sound. Of course, it only works with content you play via a compatible Fire TV device, and since it works in stereo configuration, it may not meet some people's definition of home theater.
If you want to try it out at home, connect your Fire TV and Echo devices to the same network and Amazon account. Use the Alexa app to select your audio settings, then follow the on-screen instructions.
You need a Fire TV Stick 4K, Fire TV (third generation), Fire TV Cube (first generation only and US) or Fire TV Cube (second generation). And at least one of the compatible Echo devices: Echo Dot (third generation), Echo (second or third generation), Echo Plus (first or second generation), Echo Dot with clock, Echo Studio.