Yes, the problems that befell Chelsea last season did affect the team, so their performance decreased slightly. Although many say "it shouldn't lower their performance" But we don't know for sure what happened to the team as a whole. Because what we know is what appears on the outside. It's very difficult for Chelsea to stay optimal in these circumstances.
What is certain is that Chelsea will continue to try to improve their performance at the beginning of next season even though what appears from the outside is a decline in performance because it is triggered by problems that existed last season. But overall Chelsea are still trying to make his team's performance improve next season.
All clubs certainly want to improve their performance every season, when the transfer market opens, clubs are competing to bring in new players for the same purpose. The spotlight is on Chelsea because of their failure to get the player they were looking for in the transfer market this season, Chelsea have been trying to get some top players, but the player they are after has chosen to join another club. As a big team, Chelsea is considered a failure in the transfer market, because other big teams in the Premier League have managed to strengthen their squad with several new players. It will be difficult for Chelsea to stay in the top four if they do not immediately strengthen their performance, because next season the Premier League competition will be even tighter.