Klaassen has always been like this, he captained Ajax to that Europa League final in 2017 and was player of the year in the Netherlands, always scoring important goals. It's just hard when you join a disjointed team like Everton that doesn't play to his strong points at all, in a league where you're up against ridiculously strong physical players every week. Similar when fighting relegation in Germany, even though he was one of Werder's best players. Moreso with these type of players, they've only ever played on style of football, which is the typical Ajax and Dutch one touch and move type of football. So they quite literally have no idea how to play another style.
Donny is an eerily similar type to him, both in playing style, best position and physical looks. I'd say he has a slightly higher ceiling than Klaassen - obviously at this current moment Klaassen is the better player, but Donny's technique is just little better than Klaassen's and he can match him in most other aspects of the game. In the right set-up he could be a really useful team player, but he's simply nowhere near Bruno Fernandes or Pogba's level who are his main competitors.
