People with i9s benchmarking 20k are having trouble doing software 4k in plex so I’m not surprised you’re seeing stuttering if it’s transcoding… when it seems it shouldn’t be.
I would start with seeing if it’s doing direct play or transcode… my guess is it’s transcoding
From there I would check the logs to see why it wants to transcode when obviously your TV should be fine with direct play.
You could also try some non HDR 4k samples to see if it’s the HDR tripping things up
Some threads
Reported on LG app but maybe it’s a globally affecting bug
