Did you read and follow the instructions in the first link? It actually says “How to link Homepd to Roku”. The easiest and best way is yes to use Apple TV. Apple has designed a whole ecosystem. Roku’s has also designed a whole ecosystem. If you have a Roku TV you can get the world cool wireless speakers and subwoofer to work with the tv. The sound quality out of 1 HomePod won’t be stereo either since it’s one speaker. You could however use any Bluetooth speaker and then use the Roku Remote Control app for your phone. Sync the speaker to your phone. Launch the mobile phone app and select the private listening feature. Then whatever is playing on your Roku will go through the speaker. You should also be able to do this with your HomePod mini. You can stream music from your phone to your HomePod mini right? If so then use the Roku Remote Control app
