Bellingham performed well last season. Perhaps this is why the Real Madrid management does not consider it necessary to keep Toni Kross with the squad by paying high wages. Toni Korss wants to end his career with Real Madrid. So he did not join any other club. But if the Real Madrid management had extended the contract with Kross, we might have seen Toni Kross stay with Madrid.
Toni Kroos didn't score many goals or assists. But Kross is a fantastic player. He played the most important role in stabilizing Madrid's midfield. And since Bellingham is not in the squad this season. So the weakness of Madrid's midfield is very well understood. Toni Kroos was what Madrid needed right now. However, if Bellingham returns from injury it looks like we could see a stable Madrid midfield.
I don't think it was a problem for Real Madrid to pay Kroos' salary. Now that he has retired they have much more to worry about who will fill that position. Kroos decided to retire because he felt it was difficult for him to continue playing at a high level. Real Madrid will need some time to learn to play without him.
Fonseca needs to pay attention to the defensive game because most of the problems come from Milan conceding too many goals. Against Liverpool this problem could be especially noticeable because Liverpool is an attacking team and they will look for weak spots in Milan's attack. Liverpool has been a very difficult opponent for Milan in recent years, I think Liverpool will dominate in this match too.