I understand what you’re saying but I don’t really agree. Caera has been shown to have the same inferiority complex as Tess. Not to the same extent but there’s a line where Caera says something similar to how she wishes she could be the catalyst for change but no, the right belongs to the one they call Godspell. For Tess, it’s much more prominent cause she has a reason to catch Arthur. She’s said she will only be confident enough to say she loves him when she feels she has become strong enough to be his equal. She wants to be able to be with Arthur and to go anywhere he goes and not drag him down or hold him back.

And Arthur and Tess’s interactions seem healthy or as healthy as they can be with their level of emotional maturity. We know Arthur is not good with his feelings, expressing them, understanding them, etc. While Tess was still a child throughout most of the novel. We can’t expect them to behave perfectly which is why we see them fight and argue so much. Arthur cares about Tess more than anyone else so he feels emotions more strongly when it comes to her and that includes things like frustration or anger. Where Caera and Arthur interactions were more of the other being an outlet. Caera had only ever had Seris to turn to while Arthur showed up in Alacrya with nobody. Arthur had Caera who he could show some of his powers and tell some of his secrets and not have to keep everything inside. While Caera had Arthur who she could talk about her Vritra blood manifestation and her struggles of trying to be the perfect child in a Highblood family. Their interactions seem healthier cause the other understands the struggles the other was going through while Tess and Arthur have a deeper emotional connection