Just now listened to some of her music, two of her pieces
Good Luck Babe
https://www.youtube.com/watch?v=1RKqOmSkGgM&pp=ygUcY2hhcHBlb...
and
Pink Pony Club
https://www.youtube.com/watch?v=GR3Liudev18&pp=ygUOcGluayBwb...
So, with the definition of art as the "communication, interpretation of human experience, emotion" what I saw in those two pieces was that they were intended for some teen girls and young women -- single, lonely, generally afraid of their circumstances, don't understand what they see of reality, eager for sex but afraid of it, lost, i.e., missing any good cultural, social, or intellectual foundation for understanding reality or facing life, ....
So in the music, the costumes and stage shows are rapidly changing, outrageous, meaningless, fantasy, scary, i.e., are communication, interpretation of those women's experience, emotions, rapidly changing, outrageous ....
In simple terms, those women have circumstances that yield strong emotions that the music communicates.
"Communicates"? Why? As common, to the audience comfortingly confirms that they are not alone and instead like many others.
How could this be? In the past the women lived in a culture based on strong social, practical, economic, religious, parenting forces. Now (1) for millions of those women the culture is weak or gone and (2) the Internet permits getting confirming, reinforcing communication, interpretation of their scary circumstances from the loss of the culture.
In short, the music really is communication, interpretation of the experience and emotions of those women.
To me it seems that Taylor Swift did much the same, i.e., similar audience, but Chappell Roan is stronger, louder, more outrageous for an audience with stronger emotions.
As a young man, the teen girls I knew, right, had the anxieties from their circumstances but much more constrained and less scary than now.
The music, for me, a man: Get rid of the sets, costumes, dancing, and words and take just the background music (a lot of drum beating) and the singing. In places, the singing is pretty good, i.e., expressive, but really the singing, as art, is all nearly the same, that is, the same vocal content for the same communication, interpretation of experience and emotion.
I expect that even the current devoted audience will soon, a year or so, give up on the current Chappell Roan -- for a cruel joke, "A one trick pony.".
From Vivaldi and Bach through Beethoven and Brahms ... Wagner, Tchaikowsky, ..., Barber there is a lot of effective communication, interpretation of a wide range of experiences, emotions, that is, really good art.
For level 101, a major key is glad and a minor key, sad. Then changing keys, selected chords within keys, pitch, volume, variety of sounds from the variety of instruments, combinations, ..., give a lot more tools for expression than used by Chappell Roan and, thus, permit a lot more music, art.
Next, the tools were just means, and Bach, Wagner, Tchaikowsky, ..., were really good in the artistic content, that is, again, communication, interpretation of human experience emotion.