I don't get it.
Nyalotha book-ends Uldir, with lots of parallels in each raid. We spend the entire 8.3 patch taking over and re-energizing the reorigination array. In the raid itself we are placing anchor-points to target the thing.
Then we get to the final boss, fighting in his literal brain, at the end of it we succumb to his madness but then get a whisper from the Speaker Magni that allows us to rally and we use our heart of Azeroth to act as the final anchor point and to channel the reorigination array. Ending N'Zoth and freeing Azeroth from the corruption of the final Old God.
Now I get that there's still the loose-end of the giant freakin' sword in Silithis, though there's an implication from Magni that now that N'Zoth is gone Azeroth will be able to finally heal herself. Kinda like using anti-biotics to cure a nasty infection which then let's a septic cut heal up since the body isn't fighting the infection anymore.
But what exactly is the problem?