Don't know much about him but his stats and Chelsea's record the past 2 seasons seem pretty mediocre. I'm also wary of the British player tax.Would you take Chalobah instead?
Players like van de Ven or Todibo would be good - someone promising who passes the eye test and also have decent stats to back it up. So around £30 - 40M in fees and ~£100,000pw in wages.
De Ligt apparently earns £200,000pw more than van de Ven for example. That's an additional ~£10M/yr. I don't think he's worth it and I think most fans would rather see that extra £30 - 40M invested into other players.