Samsung TV S95B Amazon Prime bad stream quality

Recently bought the beautiful S95B. Every streaming app works perfect with UHD/4K quality (Netflix, hbo, Disney+), but Amazon prime downgrades the quality. I don’t get UHD/4K.

I can’t change streaming settings in the app on Tizen. It’s 100% not my bandwidth, got 300 mb/s and all other apps works fine.

Can somebody help me with this issue?

Thanks in advance!