@ChuckPa Just updated to PMS 1.29.1 every 4k I tried played well.
CPU about 20% well within DS920+ capabilities HW transcoding HDR mapping enabled.
Really good result.
The only glitch was starting a movie to resume in the middle of the movies and some time out but the TV Plex client is quite old and so could be a client issue on the old Samsung TV Plex player.
Thanks alot great result so far,.