It is understandable that we wouldn't see them succeed on their first year with him, and he didn't even controlled the transfer window neither, he wasn't here, and he was put in charge a lot later which is a proof that Chelsea is not ready to play his style just yet.
However, if given enough time I believe that he could turn the team around and be a lot better, will be a bit difficult to handle but he can totally do that if given the chance. They will have a bit of bad results until they settle, but if given the chance for another year next season, he will do a lot better if you ask me, with all this money it is hard not to be a lot better.
The question is, how much time did Graham Potter need to get Chelsea to the title? This is a problem of course, because if it takes too long Chelsea management and fans will get fed up with having to wait long, especially if Graham Potter can't quickly build Chelsea. Like it or not, he had to build Chelsea from scratch, because the squad he had was inherited from their previous coach, Thomas Tuchel.
I hope that if Graham Potter is given longer chances in charge of Chelsea he won't let down those who put the faith in him. Because there are still many coaches who in my opinion are better than him now who are more trustworthy.
Chelsea is similar such as Manchester United that their management can provide huge money to the coaches but they seems have no patience to the process and wants the trophies and it proven that from the last 10 years Chelsea has been changed manager 7 times so Potters also has in the hot seat that if he can not able bringing Chelsea to gets the trophies in the near future i think not impossible to the management to sacked him and for Premier League Chelsea might be have no chances considering Manchester City and Arsenal are too consistent and almost be impossible to chasing them but in champion league although it's hard but Chelsea still have opportunities to gets the trophy and first step is Chelsea should be able to beat Dortmund and qualified to quarterfinal along with Potters
I think the most significant problem, in this case, is that Graham Potter is not very experienced in coaching bigger clubs like Chelsea, and as a result, he is suffering a lot.
In addition, as @darewaller said, he was brought in after the transfer window closed, so he couldn't get players to his liking. This is because we all know that coaches like to play the players they like most.
Chelsea should have brought in someone experienced, like Zinedine Zidane. Zidane is extremely talented at managing very large clubs, as we watched him win the champion's league quite a few times with Real Madrid. I think that is what Chelsea should have done.
I think what Potter needs is some time. Maybe at the end of the season, we will be able to judge whether he is good enough for Chelsea or not.
Regards
Duke