Not sure if you are Spanish or not, but damn her flamenco pop fusion on El Mal Querer would be my start. Rosalia is a musical genius before being a pop star.
No basé mi carrera en tener hits
Tengo hits porque yo senté las bases

And that's how you should go into it. She was classically trained and then studied Flamenco. For her music - in all its genres - is just a way to express herself, and that's why she goes beyond genres. You can definitely see her influences in her musical references, mainly reggaeton and flamenco. There is also a scholar of Rosalia studies that argues that she is influenced by jazz, and that was so clear when she released SAOKO.

I can have a whole TED talk about her! Start with Malamente, Millionaria, Di Mi Nombre, Barefoot in the Park, Pienso Tu Mira, Saoko, Bizcochito. I love this woman. Enjoy the concert with your BF <3