Exact same issue here. Exact same tablet. Galaxy A7 running Android 10. Please can this be looked into. Every other streaming app works flawlessly. Including running H.265 4K HEVC files over Plex so this issue is 100% down to the app. This hardware can more than support Streaming on the TV go app.
Second that the App works fine on a older Moto G4 that’s several years old. It looks like the issue is with the APP on this specific tablet on Android 10. I've done all the usual. Delete/Reinstall App, Reset Tablet, Different Wifi, Battery Modes. This is a new tablet and there have been several posts already on this topic.