I think Chelsea management doesn't seem to understand the recruitment they are doing. Even though Chelsea is a big team, they should not make blunders in the transfer window. Indeed, they recruited quality players in their old team, but when they officially joined Chelsea the new players failed to show their best development.
Then....
Chelsea is coming off one of its worst seasons in history and it wasn't due to a lack of signings because if I'm not mistaken, they invested around 300 million euros in the last transfer window, am I right?
Now, to try to "circumvent" financial fair play, Chelsea is signing long contracts to amortize the amounts in each season.... Enzo Fernández, for example, signed for an incredible nine seasons but they still need to negotiate players and try to sign some reinforcements, which is necessary, given the terrible performance they had.