I want a physical player for the CDM position, but for the CM/AM position I don't see many such players. You have Kai Havertz who I like, but there's some serious questions about his fit and him becoming another Fabregas/Coutinho.
Perhaps Fabian Ruiz, but he'll easily cost 100m+ with him being tied until 2023 and De Laurentiis' reputation as a negotiator.
It depends on the grans scheme of things. Thiago will be 29 so he will need to be replaced in couple of years and will only be a stop gap here.
What are we going in for the market? who is our targets? In general I think we need to get younger and faster. Thiago doesn't fit that.
But, if he would cost 40M (is that an estimated price?) I would go for him if we can't afford to get a high profile player like Ruiz/Havartez while rebuilding our defense and may be getting a new attacker (since we can't enter a summer without buying one)
As for Ruiz, there is a chance that De Laurentiis won't be their owner in the summer so that is huge change if it happens and we could monitor the situation for Ruiz hat could be actually bad news since Al Thani is the one who might buy them
Edit: Contract ends in 2021
40M is way too high for 29 years old Thiago, he is no Hazard for that. 25-30 and you might be on something