I wouldn't have predicted Arsenal having the season they did but I wouldn't have said their squad was as much of a mess as Chelsea's is. Just look at the players you've named, there's some serious straw clutching in there.I would suggest that Chilwell and James are top class (when fit), Thiago Silva is very good and is their only real leader in the team (is he retiring at the end of the season?).
Fernandez looks handy, they still have Kante. Pulisic, Havertz and Ziyech are good players. Kovacic is quality. Sterling is a good player and potentially Lukaku coming back into the side although he will probably be sold.
Would anyone have suggested Arsenal would have a season like this one? Well, the first 75% anyway
I think with perhaps 3 signings they will be in the mix for top 4.
Chilwell's been pretty average for quite a while now and is regularly injured. James is always injured. Thiago is nearly 40 years old and his contract is up in the summer iinm. Kante's been injured for much of the past 2-3 seasons. Pulisic and Ziyech have done nothing for years. I kind of still like Havertz but a point has to come where he needs to do something, although I don't think anybody knows where to play him. Kovacic is decent enough though.
Chelsea's best hope is that the likes of Mudryk, Madueke, Chukwuemeka, Fofana and Badiashile all come good, which is possible but it's a massive question mark.