Devola, Popola and Emil are super relevant though. Even if the game doesn't tell you so until very late, it's not like it's hidden. There are hints about Emil being more than just a merchant.
Of course, it's still a follow up in a long franchise, so... hindsight and all that.
Adam&Eve are interesting... they are indeed suicidal. By themselves, because they do one thing that is not.
But you can't really understand without knowing the entire franchise since Drakengard: the robots, like everything else on Earth, has been infected by the Watchers. That's the symbol that appears on Eve's chest. The Watchers are kinda... gods? It's never really explained, but they don't like humans. Or life in general, as humanity died thousands of years ago due to Drakengard true ending (not gonna spoil that one)... and was replaced by another type of humanity in the original Nier. And those died too, but left the androids of Nier Automata... based on Devola and Popola, the original androids!
The Watchers are real bad news in the franchise, and they are apparently not bothered by time or race. It's funny that the real bad guys are not hidden at all and appear right in front of you in cut scenes, but you don't even know it if you haven't played the rest
The robots don't need a push to destroy humanity as it is their original goal programmed by the dead aliens (maybe we'll learn about them one day, I definitely can see the Watchers helping in that matter considering that Eve is doing their work), but they need to do so
fast:
Robotic life is dying. That's not said as such in the main story, but you can learn that from the lore, from desperate robot fish not being able to survive without the original biological ones to the lack of oil for little bot dudes.
By the end of Nier Automata, things are pretty bleak for the machines, there's some cannon that end up in a robot civil war, but I don't know what to think about non game stuff when so much retcon already happened. It already contradicts a lot of what happened in the game so...
The victory of "humanity" has quite some consequences as creating new life is severely compromised, they need robots parts to create black boxes for androids... and while it's going to take some time, every sapient is going to die in-universe.
... which means that Adam&Eve's spaceship tower is the only thing that will let sapience live in outer space after all the rest is dead. And infect more stuff with the Watchers, which goes back to Drakengard actually...