Dark Fate doesn't make T2 pointless. I can understand the argument, but I disagree. T3 is an example of making T2 pointless, because its conceit is that, contrary to what the prior two films told us, it's that the future IS set, that you can't change it, and that T2 was basically a waste of time. Dark Fate is more "okay, now what?" To answer that is a film that combines the mythos of Terminator with 21st century anxieties instead of late 20th ones - drones, Internet, artificial intelligence, societal collapse, etc. It doesn't negate any of the actions of previous characters - the world is still saved from Skynet's Judgement Day, now, can it be saved from Legion's?
Of course, we'll never find out the answer to that. I'm not too fussed about that, since the majority of Terminator media treats T1/T2 as a kind of core canon, and almost everything goes off in its own direction from there. At the least though, Dark Fate does interesting things conceptually, whereas something like T3 is devoid of interesting ideas.