The whole point of T2 was that the future was not set, so John being the savior doesn't actually matter, indeed Sarah spends a large portion of T2 trying to make sure he doesn't become the savior by preemptively destroying Skynet. Dark Fate reinforced the core message of Cameron's Terminator films (1+2) which is the "no fate" line (which was originally intended to appear in the first film as well).