Music is a subjective thing, but what I like about Charli XCX is her albums have completely different sound from album to album, but are consistently fun to listen to. As if it puts you in a certain energetic mood. Listening to albums in full you can tell many tracks experiment with the genre. For example, she brought a niche thing like hyperpop to mainstream listeners in her prior 2 albums before brat.

These are some that I like from various albums:

https://youtu.be/CRYYBDG1b4Y

https://youtu.be/f-NS9hnmWN4

https://youtu.be/JsYJYUQgT7k

https://youtu.be/chSZCtLrgz8

https://youtu.be/5f5A4DnGtis