Arsenal is in fact the most successful team talking about this season's transfer window but the big question is: is that a guarantee that they will succeed when the league begins? Chelsea is one if not the most successful team during last season transfer window but we all know how it ended at the end of the season. What matters now is the players adaptation to the team style of play and the couch role too.
The transfer by Arsenal and Chelsea are different, Arsenal sign Rice, Havertz and Timber where many big clubs also looking to sign them, it's a proof where the players' quality is good. While Chelsea, they sign Datro Fofana, Andrey Santos, Mudryk, Madueke, Malo Gusto, etc out of nowhere players and no big clubs are interested with them.
There's a chance Arsenal transfer might gone wrong, but I think 8 veteran players can cover up the 3 players than Chelsea where the new players are higher than the veteran.