Flex

I receive absolutely no audio on the entire Discovery+ app and probably 25% of the Netflix movies or shows. From day one of the discovery+ app being available on flex I have logged in and logged out probably 20 times and checked it another 30 times and have never been able to get any sound though the video works normally. There's absolutely no setting available that would be responsible for this and I even called Xfinity and they told me they couldn't do anything about it and they would call me someday if they got it figured out. I have a Roku in the next room and Discovery+ works perfectly for me every time with that. I'm connected to probably another 12 or 15 apps on flex and the sound works perfectly with them all the time except for Netflix which specific movies and shows have no audio either. About 25% of the movies or shows I select have no audio but the video is fine. Every one of those shows I've ever tried on the Roku always works perfectly so it's a problem with the flex. Am I the only person in the world having this problem?