Chelsea should be able to put trust in every coach they employ, like Ten Hag at Manchester United and Arsenal with Artata. Not all coaches are able to do a great job in just one first season, even if it is not impossible, it will be really difficult because of the adaptation process.
Chelsea is completely different from other elite EPL club. They're strict when it comes to their managers and not welcoming any relenting outcomes. Erik Ten Hag in Chelsea? He would have been sacked long time ago. The previous owner, Abramovic doesn't welcome any relenting efforts or if he sensed any form of incompetence from the headcoach, he will definitely make good use of the sack letter.