Good players will perform most places they go to, and probably take their games to the next level, or at least match the required level. De Jong is a good player, so is Tadic, and they have performed relatively well in the last two leagues they have played in, with a noticeable drop in performances in the stronger leagues.
I do not expect players to perform in the Premier League, the same way they performed in the Eredivisie. Players have performed like world beaters in lower leagues, but completely flopped when they moved. It is fine, they are probably not good enough to make the step up.
So the point is that it makes little sense to say that Van de Beek played this way or that way in the Eredivisie in 2019 so should get a consistent run in our team by default based on that. Until Van de Beek shows that he is capable of playing well enough at Premier League level, then his performances in the Eredivisie means feck all and doesn't entitle him to any run of games.
The Premier League and the Eredivisie are not at the same level, as the contrast in the level of performances by his ex mates De Ligt, Tadic, Ziyech and De Jong at Ajax shows, compared to their performances in their current or former leagues. It is not about Tadic, Ziyech or De Ligt, but about Van de Beek. If you still don't get the point, then I have nothing else to say.