After some more testing it's not Bluetooth related, it's WiFi. TV was connected to my 2.4ghz SSID and my phone connected to my 5ghz SSID, with both on 2.4ghz the private listening works 100%.
So if your router supports dual banding, especially if not merged, check this as perhaps your router isn't handling band steering very well. If your router or WiFi network merges the frequencies, try separating them and check that all devices are on the same one.
If you use any kind of WiFi extenders in your home, make sure the devices are all connected to the same access point.
Welcome! Finando
It's great to hear you're able to fix your audio issue on all your apps. If you have other inquiries or problems. You can reach out here!
Cheers,
Roku Community Team
