We don't need, and obviously won't find, a replacement for Rodri. We just need somebody who knows what they are doing in midfield, can protect the defence a little and put in shift.
As others have said, our CBs have been an injury nightmare this season. if we can get one or two CBs in who are used to playing first team football, then that should give us a level of depth that, due to injury, we are lacking. Great though they both are, surely one of Stones or Ake will have to leave in the summer?
If we can get somebody who's a bit different up front and can take the load off Haaland, that would complete amazing window for us.
I've never seen any of these guys play either, but it's more the the principle of getting bodies in to give us a lift that is important. If one of two of them go on to become a major part of our future success, that's a bonus.
I'm quite excited to see how our non-Galacticos turn out :)