Apple TV 4K lower quality than native Samsung apps

Hi,

I have a Samsung qe75q90tat TV, and I have excellent quality watching Netflix, YouTube or IPTV natively on the TV.

However, my IPTV live stream was laggy at times, probably because I had an issue that the max internet speed I could get with the Samsung was 80MB (even with Ethernet and that I have 1GB internet at home), so I decided to get an Apple TV 4K (2022).

The internet speed issue is fixed (I get 1GB now), but the video quality is not the same. I'm watching football and the picture isn't as clear as watching with the native Samsung IPTV.

I have an Ultra High-Speed HDMI cable, and I connected it to the gaming port of the Samsung TV, which means HDMI 2.1.

In theory, it should run smoothly, but it doesn't. I tried playing with different settings as mentioned in other posts, and I have the latest software update on my Samsung (2505).

Any ideas?

Thanks!