Claudius I think Merino is a potential ceiling raiser, concerns about midfield balance aside. I think he's probably better than anyone else we have for that third midfield spot. I'd still love it if he were a smokescreen for Zubimendi, but...
Calafiori is the same. We're targeting weak spots in our team and getting better players. As many goals as Trossard scored for us, we need someone better than him in attack. He's basically the Jorginho of midfield, and needs pushing down. He plays wing, sometimes CF, and 8. Kai plays CF and 8, Jesus CF and wing, Martinelli either side, Saka only RW, etc. We need someone to push Trossard, Jesus, or Kai down the ranks in either the CF or wing positions, and I'd argue it's pretty doable. We're not talking about raising the ceiling above Saka (because that IS impossible), but above Trossard/Jesus/Kai at either CF or wing. I'd target Trossard as the weakest, but even better if we targeted Jesus. Havertz is borderline.
Our floor right now is Nelson, Nketiah, youth, etc. Signing someone just better than them to make up numbers feels pretty pointless if you ask me.