That happens.
The Terry-FatFrank-Cole mafia got rid of several managers, they deemed not at their level.
Potter would only have worked with a top 4 and a cup in season one, to earn the respect of world class Chilwell, Kepa, Mendy, Chalobah and Loftus-Cheek.
Both awful for the most expensive squad, 40% and 39%. Near the bottom end.
https://www.footballtransfers.com/en/transfer-news/uk-premier-league/2023/02/chelsea-best-worst-managers-history-win-percentage