Its simplistic to say but the biggest issue Chelsea face is whether their talent ID has been good enough in this restocking phase and whether they have the right footballing people in place to take the club forward.
They really should have a much better squad given the amount of money they have spent. The number of terrible transfers has been shocking, with the biggest successes like Enzo and assumedly Caicedo largely just “Congratulations, you said the biggest number” scenarios. I’m sure some of the very young players will turn out good but overall the recruitment has been really bad and every decision regarding hiring managers (Potter, Lampard as interim, Poch) also really very questionable.
If you look at the signings prior to this summer basically there were 15 players signed or loaned for big sums and 8 look really poor or at least bad for the money on early returns (Fofana, Mudryk, Cucurella, Koulibaly, Sterling, Chukwuemeka, the Felix loan, and Aubameyang), another six haven't played for Chelsea or have played so little that you can't really say anything (Badiashile, Madueke, Gusto, Santos, Fofana, Slonina), and then you have Enzo.