First of all we will not be paying a 50 for him, it will be closer to 40, then it's a great signing, because he's also on very low wages, so it's a great addition. He's definitely a talented player of the profile we need too, good casemiro replacement with more legs and overal he'd slot very well as a 6/CDM, he's productive too when pushed forward. He's got brasilian flair, so it's not liek he's only a destroyer.
And what's difficult to understand that he simply didnt feature much behind Caiceido and Enzo? He's joined as a 19year old, also alter being one of the best young players in French league. So yes he didnt show anything in Cherlsea because he's been loaned out to France. Maybe at least check his stats first before making judgement.
In today's market where Fernandes and Scott can go for 85 or 80m it's a steal and I would even say that he's at least as good as Scott who has a lot more to polish in his game and Fernandes only had a slightly better season because he played for WHU where he could getinto midfield easily and only had a breakthrough season. The next one can be his breakthrough and we should take the chance, unless our plan is different, i.e. Tchouameni. In that case we can pass because we need a more flair attacking player in midfield as well in addition to more defensive minded players which would be Tchouameni, Ederson, Mainoo...