The thing about referring to a woman embracing her sexuality as "upholding the patriarchy" is that it's falling into like twelve discourse traps that the feminists of the past already fought their way through.
Time to read just a sprinkling of feminist theory!
Marliyn Frye's 1983 essay Oppression should not be at all controversial to modern radical feminists; its conclusion is that men are not oppressed as men, even if they experience deprivation for other reasons or are oppressed as other identities. But when I first read it in my feminist philosophy class in the mid 2010s (right before reading Crenshaw's essay on intersectionality, which complicated Frye's conclusion) the part that stuck with me was Frye's evocative metaphor of a birdcage:
Consider a birdcage.
If you look very closely at just one wire in the cage, you cannot see the other wires. If your conception of what is before you is determined by this myopic focus, you could look at that one wire, up and down the length of it, and unable to see why a bird would not just fly around the wire any time it wanted to go somewhere. Furthermore, even if, one day at a time, you myopically inspected each wire, you still could not see why a bird would have trouble going past the wires to get anywhere. There is no physical property of any one wire, nothing that the closest scrutiny could discover, that will reveal how a bird could be inhibited or harmed by it except in the most accidental way.
It is only when you step back, stop looking at the wires one by one, microscopically, and take a macroscopic view of the whole cage, that you can see why the bird does not go anywhere; and then you will see it in a moment. It will require no great subtlety of mental powers. It is perfectly obvious that the bird is surrounded by a network of systematically related barriers, no one of which would be the least hindrance to its flight, but which, by their relations to each other, are as confining as the solid walls of a dungeon.
Frye used this metaphor in the context of explaining the twin pressures to not be a slut AND not be a prude, illustrating how women are kept caged by a society that justifies punishment for both sexual availability and lack of sexual availability:
It is common in the United States that women, especially younger
women, are in a bind where neither sexual activity nor sexual inactivity is all right. If she is heterosexually active, a woman is open to censure and punishment for being loose, unprincipled or a whore. The “punishment” comes in the form of criticism, snide and embarrassing remarks, being treated as an easy lay by men, scorn from her more restrained female friends. She may have to lie to hide her behavior from her parents. She must juggle the risks of unwanted pregnancy and dangerous contraceptives.
On the other hand, if she refrains from heterosexual activity, she is fairly constantly harassed by men who try to persuade her into it and pressure her into it and pressure her to “relax” and “let her hair down”; she is threatened with labels like “frigid,” “uptight,” “man-hater,” “bitch,” and “cocktease.” The same parents who would be disapproving of her sexual activity may be worried by her inactivity because it suggests she is not or will not be popular, or is not sexually normal. She may be charged with lesbianism...
It's been forty years since this essay was published, but the situation hasn't improved all that much with regard to the slut/prude double-bind. Women are pressured to be modest AND pressured to be sexy. If you're good at balancing these pressures, or if your personal style falls naturally ("naturally"🤔) between them, you may not even notice you've been caged. You may look at a woman in modest Mennonite dress and assume she has succumbed to the pressure to be modest; you may look at a woman in a push-up bra and a miniskirt and assume she has succumbed to the pressure to be sexy. But consider: did you yourself succumb to the pressure to be neither?
I had to dig back over ten years to find this comic by @rosalarian, but I'm glad I found it, because it encapsulates the problem pretty perfectly:
There is pressure to be sexually pleasing to men and there is pressure to NOT be sexually pleasing to men. This is not some "men want you to be slutty and feminists want you to be a prude" thing: BOTH of these pressures come, ultimately, from the patriarchy! The unifying theme is that women's sexuality should be entirely under male control; women should never make choices about their sexual expression based on what they personally find gratifying. They should entirely restrict their sexual behavior to whatever the nearest representative of patriarchal power happens to want in the moment, whether that's saving themselves for marriage or stripping for the camera.
The reason women are more likely to have careers based on "embracing their sexuality" is they're more likely to be forced to justify trying to look extremely sexy on purpose. Trying to look extremely sexy (and sexually available) on purpose is not limited to female pop stars by any means, but Sabrina Carpenter aggressively dressing like a pinup is political in a way that Harry Styles in leather pants with his tits out is not.
So it's time to drag out another classic of feminist theory: Deborah Tannen's 1993 article There Is No Unmarked Woman.
(It's a very short article and I'm reproducing nearly half of it in this post, so I encourage you to read it in full.)
As I amused myself finding coherence in these styles, I suddenly wondered why I was scrutinizing only the women. I scanned the eight men at the table. And then I knew why I wasn't studying them. The men's styles were unmarked.
The term “marked” is a staple of linguistic theory. [...] The unmarked form of a word carries the meaning that goes without saying -- what you think of when you're not thinking anything special.
[...]
Each of the women at the conference had to make decisions about hair, clothing, makeup and accessories, and each decision carried meaning. Every style available to us was marked. The men in our group had made decisions, too, but the range from which they chose was incomparably narrower. Men can choose styles that are marked, but they don't have to, and in this group none did. Unlike the women, they had the option of being unmarked.
Take the men's hair styles. There was no marine crew cut or oily longish hair falling into eyes, no asymmetrical, two-tiered construction to swirl over a bald top. One man was unabashedly bald; the others had hair of standard length, parted on one side, in natural shades of brown or gray or graying. Their hair obstructed no views, left little to toss or push back or run fingers through and, consequently, needed and attracted no attention. A few men had beards. In a business setting, beards might be marked. In this academic gathering, they weren't. There could have been a cowboy shirt with string tie or a three-piece suit or a necklaced hippie in jeans. But there wasn't. All eight men wore brown or blue slacks and nondescript shirts of light colors. No man wore sandals or boots; their shoes were dark, closed, comfortable and flat. In short, unmarked.
Although no man wore makeup, you couldn't say the men didn't wear makeup in the sense that you could say a woman didn't wear makeup. For men, no makeup is unmarked. I asked myself what style we women could have adopted that would have been unmarked, like the men's. The answer was none. There is no unmarked woman.
The woman in the teal shirt and jeans in Rosalarian's comic thinks she is unmarked. She judges the other women for 'marking' themselves. But she, too, is marked; she cannot escape the patriarchy cage simply by splitting the difference between slut and prude.
Similarly, OP is comparing Sabrina Carpenter's marked-ness with the way male celebrities are unmarked. OP imagines that Sabrina could base her career on "being a person" if she ditched her slutty pinup style. But do more modest female artists actually get to do that, as a rule? There are a million articles and studies about discrimination against women in the music industry. Plenty of stories exist about the forced sexualization of female artists who actively did not want to be sexualized. But OP isn't digging into any of those: OP is most distressed by the female artists who are vocal about choosing and controlling their own sexual expression. And that, unfortunately, means OP's concerns are 100% aligned with the patriarchy on this issue.
There's a surface-level feministy reason for this, in that if you are distressed about women getting forced to be sexy when they don't want to be sexy, you're afraid that a different woman saying "Actually I really enjoy being sexy and I'm doing it on purpose" is going to provide convenient cover for the victimization of the unwilling.
But that kind of concern has always been a cop-out. If women aren't allowed to say yes to sex and sexiness, then you are not actually advancing the cause of female sexual autonomy. You're just saying that the patriarchal pressure to NOT be a slut is more acceptable to you than the patriarchal pressure to BE a slut.
You have to reject both pressures. The pressure to dress sexy, the pressure to dress modest—they are both the patriarchy trying to control women. Neither is legitimate.
If a woman is less of a person because she's too sexual, the patriarchy is winning. If a woman is less of a person because she's not sexual enough, the patriarchy is winning.
If a woman is less of a person for literally any reason, the patriarchy is winning.
Do not let the patriarchy win!