Replace Fernando with Kante.
Kante release clause of 20m, age 25 (just)
Could get around 12m for Fernando, age 28 (29 next month), so next to no outlay
The option of pairing Kante and Gundogan with Silva or KDB or Dinho, depending on the game, could work well.
Based on last season, Kante and Gundogan would be making over 7 interceptions per game between them! That's a big increase on 4 (Dinho+Nando), 3.1 (Toure+Nando) and 2.8 (Toure+Dinho), not to mention you get a lot more mobility (pressing), the same number of tackles (5) as our most defensive pairing of Nando+Dinho with the intelligence and creativity of Gundogan.
And if you were to play Kante, Gundogan and Dinho in a game you'd expect to see around 8 tackles, and 9 interceptions between them...
Obviously stats don't always carry over into a different team but these show what the players are generally capable of, it's clear Fernando couldn't do what Kante does.