Chelsea coach Graham Potter is not very experienced. The most renowned club he has coached in his career is Chelsea. So it would be foolish to expect him to bring the Chelsea team to the title, or to improve Chelsea's performance very quickly. We are not sure if Graham Potter will be able to do anything good at all. So I don't have much faith in Graham Potter. Thomas Tuchal was more experienced than Potter. He could not stabilize the team this season. Chelsea need talented players now. I don't think Chelsea's performance will improve if they don't add talented players to the team.
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.