Chelsea need to get rid of some names soon because the club has collected a lot of players and it is not good for their finances at all. Sancho is not the same player as he was at Dortmund, he has struggled quite a bit this year, maybe he should be returned to Man Utd and replaced by someone else, namely Joao Pedro, because he can be placed as a winger. No need to worry about his quality, I think his statistics are quite good, 10 goals 6 assists in 27 games with Brighton shows that Joao Pedro has potential + he is still very young.
Sancho was already returned to Manchester United as Chelsea has made it clear that they can't pay him the salary that he's demanding. Chelsea has been active in the transfer market, signing new talents and young ones too therefore Chelsea are already looking for replacement for some of the areas they didn't have strength in. Chelsea are showing that they're ready to compete with the rest of the clubs. They already have lots of players but that isn't stopping them from signing new talents when they see them. The people in charge of the recruitment at Chelsea are doing a great job. The benefits will be in few years when they start selling the young players for profits