Since the right people are here, can anyone explain to me why its so hard to "root" (in reality, obtain basic filesystem / networking etc. control) with that OS?
GrapheneOS is focused on being as secure as possible. When you put root access into the equation, all the security protections are irrelevant if apps are able to bypass them at will.
It's really not that hard to do, just antithetical to the purpose of the OS.