I took a look at his CL games and it seems he only played against two PL teams.
Chelsea as DM, one match lost by 0-1 and one 4-4 draw. And then Liverpool two times loosing with 0-1. Don’t think that is enough to evaluate him for PL, it will sure be a risk taking.
He was a midfielder when he was bought by Ajax though and it was Ten Hag (I believe) who moved him to CB because his attributes there, along with Timber, suited the style and system he wanted.
With Ten Hag saying that midfield and attack are our priorities, I wouldn't be surprised to see him return to the position he played in up until around 2019 and potentially be used as a utility player as well to fill in on the left or at the back, should he need to.
It seems to me that his versatility and main strengths (aggression, ball winning, ball progression and passing) could see him playing a couple of different positions. With Ten Hag's apparent stance on Maguire, I don't see him dropping Maguire or Varane at CB and I wouldn't be surprised to see him play like 70% of games in midfield, with the others being split into some games at CB and maybe a couple of games at left back or in a back 3.
Could be a brilliant signing though. Tenacious, tough, no bs style of player. His nickname of 'the butcher' is one I can see our fans picking up quite happily as well. He's also at a great age, having not long turned 24. The character and mentality he'd bring in is something that could see him ending up as a bit of a cult hero with.
Martinez, Bruno and De Jong is (on paper at least) an elite midfield. It has everything from energy and work rate to creativity and aggression as well as being so much more press resistant to a pivot of Scott and Fred. It can keep the ball, progress it, win it back and create moments of magic. Theoretically we go from having a midfield that's probably in the bottom 25% in the league, to instantly being one that's more like in the top 25%