I'll add she has a very interesting take on Bobbie. So often he is a cipher, charismatic but unknowable. Her Bobbie does keep her cards close to her chest, but is quite gregarious, goofy, and game. In a benefit to making Bobbie a women, her independence feels much more about keeping her sense of freedom to play. She's far less a wallflower than male Bobbie's can be and it makes her big numbers at the end of each act stand out.
As for her vocals, she's not a high belter. They knew this when they cast her. When I first heard the London recording, I remarked how high these keys are for a woman. And if they'd wanted someone like Cassie Levy, who could belt the sh*t out of it, they'd have gone that route. We know Sondheim always prefers actors who sing (no judgment on Levy, obviously, and she's wonderful in Caroline), so likely the belt is far less important to him. Hell, maybe he prefers a mix! Anyhow, she's giving a wonderful performance that, yes, has to work overtime with a supporting cast like that!