2 days ago Google released update for Youtube for Android TV and here are notes:
• Reduced CPU usage
• Improved Network throughput
• Added Opus support
• Reduced frame drops on some platforms
• Resolved crashes that can occur in some instances
• Various other platform improvements
I can say the improvements are certainly visible on Sony 55XF7596, 4K/60fps is watchable without periodic stutters.
I wonder if this fixes the audio pop I get when moving ahead in a video. I'll have to check when I get home!