The problem is this doesn't really work anymore with Widevine protected content. You are not getting Widevine L1 protected content through Windows or other type of home desktop operating system. Even without L1 content, platforms like Youtube won't serve 5.1 surround unless it's through an app and not the browser.

I'm not saying you need a smart TV, but if you want to get the content you're actually paying for via Netflix, HBO etc in the highest quality they offer, you'll need to fork over money for a device with dedicated hardware