In return for you
https://www.scottaaronson.com/blog/?p=3975 for a fundamental flaw in the Nature paper.
As for the differences between Convivial Solipsism and Many Worlds, I am indifferent to them. It is immaterial to me whether I am a singular observer who can only be aware of part of the wave function, or I am one component of a superposition of observers, each of which is only aware of part of the wave function.
I personally lean away from solipsism because I do not think that I, or my observation of reality, are that important. But that is a preference. And I don't have any particular justification for it or reason to disagree with anyone with the opposite opinion.