O.k., obviously Atom & Nuka were at the very least attracted to each other, & they shared certain design features, one might say they were cousins, at the very least. Granted, their attraction was because they were robots in a world of humans, dominated by humans. They were robots about the same size, with similar intellectual capacity, etc. Though Nuka apparently knew why Atom had come, she was so lonely, that it mattered not.
Atlas, though built much closer to Atom's design, hated him, but only because they were on opposite sides of the law. Atlas apparently did have an unconscious affection for Atom, seeing that he let him off on several occasions. Libian had to remind him of their relationship, though Atlas had tried to forget about it. He found himself unable to go all-out in his fight against Atom, & may have wondered why. But Atlas & Atom would have been friendly had not Walpurgiss forced Atlas into crime, & met Atom as an opponent.
Recall that Robio & Robiette were attracted to each other because of their similarities. Though their creators were competitors, their ideas for them resulted in similarities; & hence, attraction.
On the other hand, Mars & Agnes had no such similarities, yet there was apparently more than just empathy between them.

Every boy in class, including Shibugaki, was throbbing

s for Agnes. Without a doubt, 1980s #52 was inspired by Jetter Mars #19,
MARS' 1ST LOVE, though it did introduce elements of its own. Would Atom have risked himself in an apparently hopeless task, otherwise? Would Nuka have risked herself without true love?