Almost all commercial and amateur (on YouTube) video content is in 4:2:0. People don't need the meaningless 4:2:2 either. Who needs full quality - they write in 4:4:4 without color loss. Support for 4:4:4 has long been announced by NVidia and Intel, and AMD, as usual, hides all the specifications, it's impossible to find anything on their website. They even began to publish extended data about processors from 2022 only! I somehow tried to reliably get support max mem by cpu mem controllers from them, so their support could not even clearly answer the question according to the information that Intel clearly lays out right away for all series. While Intel has begun to hide the peak bandwidth of memory controllers for a particular type of installed memory, for example, in view of the apparent inconsistency of their declarations with past practice. At AMD, it's just not healthy to get complete datasheets for fresh processor lines and their built-in igpu without wild ordeals.
Moreover, they announced 4k support back in Zen+, but in practice it turned out that their iGPU simply does not support 4k@60Hz - continuous drops and the load on the iGPU is above 60% is simply monstrous (against the background of smartphones). As a result, in 2020, AMD recognized the impossibility of hardware smooth decoding in Zen+ and Zen2 and made a hybrid decoder for them - which dramatically increased the load on the CPU part (from 5-7% to 15% and higher on YouTube in VP9). But the drops are still there in Chrome.
If we talk about absolutely smooth playback of 4k@60fps, then in practice, NONE of this trio - AMD/NVidia/Intel - provides smooth playback of 4k@60Hz with VSync on their chips. Occasionally, drops or a visible disruption of synchronization (VSync) occur (even if there are allegedly no drops according to statistics).
Until there is an ideal playback like hardware players or how the chips of this trinity can play fhd@60fps for hours without visible VSync disruptions, it is impossible for those who are in the subject to give them 100% playback quality.