Director Scott Derrickson was responsible for the first installment and then left his place in Doctor Strange 2 to Sam Raimi.
Marvel Studios hired Scott Derrickson because he had gained a lot of fame as a horror director and even though he was in charge of the 2016 origin film and had signed on to do Doc Strange 2, decided to leave the sequel due to creative differences. This caused the project to pass into the hands of sam raimi. The end result has been an incredible success because it has already raised more than 950 million dollars worldwide.
“Well, I wasn’t working on the movie. I was working on other things. So we didn’t have to do any soul-searching because this was the movie that we already had set up for Scott to do after Doctor Strange 2. When we wrote it, we thought, Well, Scott is going to become Strange, so he won’t be able to direct it. So we sent it to two directors and luckily they both approved it.”
“But then Scott said, ‘I really want to direct this one. I want to make this movie. I have to make this movie. We can wait? He knew it was a big order for me because it was something he had written and we weren’t going to sell it until it was time for him to do it. So that could mean a couple of years before we were able to pull it off, but I was like: You know what? I will wait. Yes, I want you to direct this. I think it’s right. Let’s wait and do that. So he was ready, and as soon as he left Doctor Strange 2, the answer was: We’re going to do The Black Phone ». I conclude C.Robert Cargill.
So it looks like Scott Derrickson was really little involved with Doc Strange 2 before leaving the project, since he was more interested in dedicating himself to The Black Phone.