There's a lot of fun contrasts between 9S and 2B, and I think one of my favorites is one that ties into their potential for queer readings that I mentioned earlier.
We are told in no ambiguous terms that 9S's attraction toward 2B is sexual in nature. This isn't exclusive of other kinds of attraction—I think textual evidence can be found for romantic, aesthetic and intellectual attraction, for example. And don't even get me started on the headcanon potential. But the sexual element is specifically pointed out within the text.
But 2B's attraction, to my knowledge, isn't assigned a specific form or nature. Obviously, NieR has so much lore that it's probably super difficult to scour EVERYTHING, especially with that archive website taken down. Also, the nature of it being a multi-ending game makes it a bit hard to get every single bit of info in every single ending. 😓 ANYWAY, from what I've seen, the ways she expresses it leaves it more open to the reader's interpretation: it could be romantic or sexual, but it could also be platonic, familial, sensory, or something else entirely. I think there's a lot of depth to be explored there in terms of how hers doesn't mirror 9S's exact experience, even though there are certainly psychological similarities to how they deal with their attractions.
On a tangentially related note, given that this attraction seems to come up no matter the iteration or form of each model (e.g. NieR:Automata game vs. YoRHa Boys), I could argue a pansexual reading for 9S/No. 9/however else this consciousness exists in whatever parts of the lore I haven't read yet. And there are DEFINITELY many things to be said about "straight-passing" relationships that are nevertheless queer as heck.
I don't have a pretty ending or conclusion for this. This is just where my brain has been going the last day or so.