Your so-called 'educational' video was an infamous click-bait NONSENSE widely promoted on Youtube for about a month a few weeks back. Most of the 'popular' 'science' videos on Youtube are total fabrications- but Google doesn't care so long as they make good ad money. The MSN (microsoft) frontpage was serving up one of those fake "your computer has a trojan infection" ad only a couple of days back- again MS is happy to take their share of the ad revenue.
At a close distance, the effective resolution of the Human eye is way greater than 4K. Human vision is also very good for RELATIVE colour and brightness detection as well, but not absolute.
And did you know ALL males are 'colour blind' if by colour blind one means a Human with less than the optimal colour receptors in the eye. A small number of females are tetrachromats- they see a range of colours no male can ever perceive. A mutation gives them FOUR types of colour receptors (and their male children, if they have any, severe traditional colour blindness).
Anyway, back to Google's promoted fake news. If you stayed awake during your high school biology lessons, you'll know the Human eye has a 'blind spot' (where the optic nerve attaches to the back of the eye) and vastly inproved resolution perception at the centre of the vision surface. You may also have leaned that a lot of what we think is seen is actually pre-processing in our vision system between the eye and the brain (hence the reason a lot of optical illusions work). This processing means the 'blind spot' normally has no impact on our detail vision.
When close enough to a 4K monitor to benefit from the rez, one perceives the 4K effect in various ways- video motion and eye/head motion play a part. For instance ever wonder why many birds rapidly move their heads? Having eyes on either side of the head means that birds' eyes have a wide field of view but ZERO stereo depth perception for close objects (like when on the ground looking for prey). By rapidly bobbing the head, the bird brain can replicate a stereo effect per eye by placing each eye rapidly in two positions.
When the human head or eye moves, edges transition across cells giving more information. Animal vision is a lot more complicated than simply cosnsidering a static pixel cell reception system- but even there the rez of our receptors where we perceive detail is better than 4K.
The lesson is to NOT get your science understanding from promoted clickbait on Youtube or other mainstream ad-revenue driven Internet giants. Wikipedia, while utterly terrible for anything with a 'political' dimension, is quite good as a starting point for most basic science/maths.
The clickbait pseudo science is made by the same techniques as ads- designed to seem plausible for the ill-informed. And in this regard, Youtube has been getting much worse of late. Google (the owner) has the worst people as partners. Yet Google will wage war on channels it dislikes, ensuring they get no promotion on Youtube unless you very explicitly search for them.
But then go to metacritic and look at the 10/10 'user' reviews for FO76- written by paid troll farms in India using the same weird english mini-essays one sees on the IMDB when a studio pays for a similar service to boost the score of their new movie there. You cannot take what you see online at face value, especially when it links to Big Media.
PS only two days ago Youtube promoted another NONSENSE video - what would happen if Russia's biggest nuke was exploded in the ocean's deepest trench. Like the 4K nonsense video, it was promoted as 'educational'- although after a few days of release the 'authors' had inserted "this is just a fantasy" into the video's description after real science sites (that Youtube NEVER promotes) ripped it to pieces.
Funny thing is the comments to such videos are the best place to learn the 'truthiness', tho many people do claim they cannot distinguish between the educated comments and those from fools who buy everything in the video hook, line and sinker. And most scary of all, some people make a point of NEVER reading the comments in the belief that no-one has the right to challenge or critique the author.
PPS 'did you know' can curse proper science understanding as well. For much of the 20th century, skin grafts were HORRIFIC because whole sheets of skin had to be used (and thus removed from elsewhere on the patient). All this because a famous medical book FALSELY claimed you could not grow skin grafts from scraped skin cells.
Another famous teaching medical book completely and falsely described the cause of stomach ulcers. Only recently did Austarlian scientists challenge the utter falsehood that all doctors were taught- and discovered that ulcers had the simpest treatment imaginable. And even then it took TWENTY years for the PROVEN new science to be fully implemented by doctors across the West. In that 20 years, many ulcer patients continued to suffer terribly because their doctors couldn't be bothered to update their knowledge, and prescrible the correct (and very cheap) drug treatments.
PPPS this can effect even those people you THINK the brightest. In his terrible popularist book, Hawking stated with 100% certainty that either our universe was expanding, but the expansion was ever slower. OR the universe would reach a point of maximum expansion and then contract again. Of course he was 100% WRONG- a few years later it was conclusively proved that the universe is expanding, and the expansion accelerating. Three possibillities, and the one Hawking claimed could never be was the one that is.