A midfielder of his profile is needed. He could rotate with Mainoo as a B2B or play as a 6 behind him. He would be a good fit for the squad and shouldn't cost more than 30m given he's in his last year of contract. I would prefer Amadou Onana as a starting 6 but given his likely transfer fee and our budget, Fofana might be a more sensible option. If we don't go for Fofana, I think we should look at Lucas Gourna-Douth. We could bring either one of them with Archie Gray as squad option, who can play as a 6 and be a 3rd choice RB. Then we would never be in a position to rely on McT as a deeper midfield option and he can focus on his best role, as an substitute from the bench, coming in as a box crashing 10 when chasing a game and needing a goal. We would probably have enough in the budget to chase someone like Doue, who we've been linked with.
Imagine we move our midfield composition from this:
Casemiro/Amrabat Erikksen/Mainoo/McT
Bruno/Mount
To this:
Fofana/Gray Mainoo/Mount
Bruno/McT