Yes. Kinda annoying that they leave this out and just straight spoil others that she tried to kill herself when in fact it was a misunderstanding on Kael's part.
Also, on the decision to oppose the abdication, Kael's reason was because he thought that if Hess goal was to get Diana to apologize, even if it was unsatisfying, she had already achieved it and he wants to move on and focus more on them as a couple. She was disheartened that he easily forgave her and had a little contemplation (she already knew she can't leave by dying, so she had no thoughts on killing herself-) on her purpose after Kael's decision.
After the balcony incident, Heli talked to both of them and made Hess realize that the revenge she wanted was not Diana's abdication but her sincerely regretting her actions.
---tbf Heli and Kael's reasons made sense and not simply because of trying save Diana's face, especially Heli's part. Hess was getting kinda too focused on abdicating her when in fact it would only make Diana think of her more as an enemy rather than her reflecting on her actions (she's just too self-centered for that). What she initially and actually wanted was to make her regret her actions towards Kael. (Heli already redeemed himself at this point so he's excused)
If u guys want to read this part, it's here:
https://moonlightnovel.com/for-my-derelict-favorite/fmdf-chapter-32/
So stop believing spoilers without context and go on hate rage for the character without giving them a chance.
Ok she doesn't really tries to kills herself later in the story she's at the balcony looking down thinking oh of I jump will I return to my original world type not the type of I wanna die I have no hope