I feel fandom has coopted <> mostly to mean platonic love but doesn't it mean more, one person calms the other one down and keeps them in check in canon? Isn't that kinda one-sided? Like what did Eridan for Feferi? What did Equius for Nepeta?

No no, first of all while it looks Platonic-ish, it’s still a Quadrant of Romance. Eridan and Feferi had a toxic Moirailship, with Eridan being too draining for Feferi to handle. But Equius and Nepeta, on the other hand, do have a pretty comfortable Moirailship that’s not one-sided- Equius is bossy and pushy, yeah, but Nepeta is kind of wild and reckless. He makes sure she doesn’t get into any big dangerous messes, and she calms him down when his blood starts to boil, and they vent to each other. Equius also humors her with roleplaying occasionally and show to be quite happy once they meet in person rather than spamming each other with ‘yes’ ‘no’ conversations on Trollian. This relationship balances the two of them out nicely, and showcases a more healthy display than, I believe, anyone we have seen? At least because it’s the one we’ve seen the most of.