Xbox one S doesn't run at 4k?

I got a new TV that should play 4k Uhd.

But if I set it on my xbox, I have the bad picture. I do not know if it is because of the tv, the xbox or my hdmi cable. I really tried everything and I'm getting really desperate.

ok odl 50750us-tib is the name of the tv

Technical specifications:

product type

LED TV

screen form

Flat

picture quality

UHD 4K

Screen diagonal (inches)

50 inches

Screen diagonal (cm)

127 cm

SMART TV

Yes

types of reception

DVB-C, DVB-S, DVB-S2

Please help me, I bought this tv specially to get a nice picture and now it's bad denje.

I'm looking forward to your Answers.

https://beta.support.xbox.com/help/hardware-network/display-sound/tv-resolutions

I've already looked at that. Didn't help, unfortunately

Try a different HDMI cable first

Have already tried two different ones that I had here. Which hdmi cable do I need?

So to display 4k up to 30 Hz at least a 1.4 is necessary…

You will have it for sure

Then it is not because of the HDMI cable.

I tested 2 different ones

Is it in the right input on the TV? Especially with these cheap it may be that only one input is HDMI 1.4.

In the TV settings I can choose whether 2.0 or 1.4. It is currently set to 2.0 and is in the number 1 connector

The TV may recognize that it is only upscaled 4K and not native 4K.