Why is my Samsung TV juddering?

I recently bought a Samsung QLED TV (model Q75T). I'm actually quite happy with the part. However, I notice that it doesn't always run smoothly. If I z. B. Start the YouTube app via my Xbox Series S, then there are some videos (especially older ones) that are displayed with jerks.

I could also observe that some thumbnails show a very slight flicker. Gaming and Netflixen are otherwise doing relatively well.

My question would be if anyone is familiar with the image settings? Is it perhaps because the television can't process old video material well? Or do I have to do something in the expert settings?

Are you doing this on SMART TV or on a PC?

Do you see that with the XBox? Then it's up to your XBox.

I just plugged my TV into the Xbox. I don't use a PC. The TV has an HDMI 2.1 connection, but I still need a cable to get the full potential of the console. The jerks are also there when I watch YouTube on the Samsung TV app. I just wonder how to get rid of this.