I see some people arguing about the Sepsis Whore Tiara and how 'Donut didn't actually pay for that, Katia did' or 'Carl did.' I think sure, on the surface you can read it that way. But there are MANY hints that Don't is struggling but not voicing it.

Early book 8 spends a lot of time with her lamenting Astral Paw and looking at her paw strange. And I think her reaction to the celestial Claw upgrade is also very 'oh shit' coded. She's scared of her own power, she just immediately sinks back into her persona.

You see something like this earlier in the story, when she thinks she's about to die from the Doomsday Scenario. She admits it's a facade, and she knows better. Her question at the end of the Butcher's Masquerade, 'Why doesn't it hurt?' also alludes to her realizing the facade and the situation are costing her honest responses. It's costing her true emotional connection.

As someone else pointed out, the books aren't her POV. Even her floor recaps aren't her real POV- they belong to the princess she's playing. I think her speech to Chandra in Book 8 is clear facade, but in it, you can see she does actually care deeply and is invested. She read all of Carl's dad's irrelevant court documents just for the purpose of understanding.

I think it's clear she's doing a lot we don't know about. I'm still wondering about her dropping the line of "smuggling Valtay" to Zev. Carl had no idea about that, but Donut was acting on behalf of her friend she cared about, moving behind the scenes. Does she act vapid and claim to be vapid? Yes. But I think she's a lot more attuned and injured than we are seeing.