Google home can't play music on samsung HW-990B using google assistant

Hey, I connected SmartThings app, added my sound bar later on i added SmartThings sound bar to google home. when I ask google assistant play music on the living room sound bar it says - “sorry i don’t find any devices on your home that can play music”. I can play music from spotify and select sound bar as an output and works. why google home can’t play music on sound bar when it’s visibly added there? how to setup that sound bar as a default home speaker? (i don’t want to connect it as a default speaker to google mini via bluetooth because it’s laggy). On SmartThing application sound bar is visible i can control it but google nest mini doesn’t allow me to play music on it directly and says the error that i previously mentioned