Same issue here on both our Samsungs with 5.29.1, one is platform 3 and the other is 4. Everyone seems to be talking about the slow UI issue, whereas I’m more concerned that I was unable to watch the first two things I tried, seems a very bad build. As a workaround, I was able to use the web client via the internet browser on the newer of the two, but the older tv doesn’t manage to load the site, just sits there at the Plex logo.
Edit: Downgrading didn’t fix the issue for me, turned out to be this: Samsung TV Connection Problem - #11 by team414 - to be clear, I went into the server settings, Network tab, set ‘Secure Connections’ to preferred - not sure if that is excessive but fixed it. So no need to disable Direct Play/Stream, and also works with latest server 1.25
Edit 2: Unfortunately, the fix above only worked for the 5.29.1 on the newer platform 4, the older Samsung still has the same playback error so I have no solution for that.
Edit 3: Fixed the other tv too - I had to hold down the Back button on the remote to kill that app - reopening it, it is now using the new secure connections state.