I know it sounds cynical, but I'm kind of convinced that a lot of it is exaggerated.
Maybe her mental health struggles are not the actual reason for failure, so much as it is a defense measure/brand protection measure when she fails to succeed through simply not being good enough at a certain time/place.
For instance, yesterday, she shyt the bed. In short order, she transformed the storyline from one of a heralded athlete failing to meet expectations and underperforming, to one of a heralded athlete undone yet again by forces outside her control (the press, the referee, the tournament, the a$$hole fans, etc.). That's what everyone is taking away from this; not her actual loss. And, as a bonus, she manages to compare herself to the Williams sisters in a "standing on the shoulders of giants" moment, and has everyone following her lead. It's brilliant brand protection.
If it were calculated, of course.