If every season Chelsea always replaces their old coach with a new coach, of course Chelsea will always find it difficult to find more wins in every new season they live. Because every new coach is different in the way they train players and also different in how they read the players' character, so changing coaches in each season will actually have a big influence on the good and bad of the team's performance. Although dominantly it might be worse if the coach was not experienced enough in coaching an English team like Chelsea.
Chelsea has officially fired Pochettino this season, even though Pochettino was able to improve Chelsea performance at the end of the season and bring Chelsea to play in Europe next season, this does not make Chelsea management continue to collaborate with Pochettino, who actually still has one more season with Chelsea, previously, Chelsea hadls fired Tuchel from the coaching chair because Chelsea performance was deteriorating, but to be honest, I am quite confused about what Chelsea management actually wants at the moment, because they continue to fire coaches even though Chelsea is currently moving in the same direction better with pochettino.
Chelsea should be able to learn from Inter Milan mistakes and Napoli frequent changes of coaches, Napoli even slumped this season after changing coaches 3 times, frequently changing coaches will of course make the players continue to start from zero in understanding the strategies implemented by the new coach, because the strategies and training patterns applied by each coach are very different and in fact this makes it take a long time for the players to understand the new training patterns later.