Neither Mueller, Barr or the president are above the law. That's why its written in law. If you are interested in why the report in its entirety aren't legally allowed to be released publicly you can look up Ken Starr and what you will find is that it was the democrats that introduced the laws that prevented reports such as the Mueller report being released in their entirety. The laws were introduced to prevent people that contributed to reports being publicly named and to protect sensitive information not relevant to the investigation.
The legal shitfight you refer to is the US democrats fighting against the laws they themselves introduced after the Clinton investigation.
