I prefer Librewolf as it is easier and simpler to use
It is a script that automatically changes the internal flags of Firefox (accessed manually through “about:config”) but isn’t a recompile. A fork that uses most of the Arkenfox config is Librewolf.
Arkenfox quite literally is not a fork. It is just changing settings. That is like saying I am making a Firefox fork by changing it to dark theme and changing the default search engine to Bing.
Arkenfox isn’t a fork, even with a script it is manual for much of it. A fork requires redistributing the code, which for Firefox requires the Dev to change the name and replace icons of the application (to comply with Firefox’s license), which requires modifying the source code and compiling.