Have you tried using a different HDMI port on your TV as well as switching out the HDMI cable used to connect your device? For troubleshooting purposes, have you also tried plugging in your device into another TV to see if you experience the same issue?
Yeah none of mine have audio only the menu sounds. My other roku TVs work fine just not the 50 in rca one I called walmart and they are sending a replacement. I’ve spent 4 hrs troubleshooting and I’m done. Lol I work in tech support and can’t think of anything else besides a hardware bug.