If you are going to trust some Youtuber making up rumors, I don't know what to tell you. Iger has been looking to retire for a long time. Well before any of the Star Wars backlash.
On the opposite side, I can also say that if you think that the problems related to Star Wars have nothing to do with his choosing now to quit, then I don't know what to tell you.
In the end, I'm not going to pretend like I'm certain about it. I was listing it with a number of other things that show that there's a problem.
I'm willing to be wrong if I am, but all the arrows point to the same direction.