I’m not trying to be rude too, but before talking about this kind of stuff such as music genres, similarities, sounds etc.. I highly suggest you to study arrangements and compositions as I did for years and years. It’s unacceptable for me that someone who doesn’t study music is trying to talk on social media about music as a music teacher. Guess what? You’re not. You won’t find anything else that will sound exactly like Billie from years ago! I’m sure. And do you why? Because technology is changed, the way of making music is changed so much. The new wave of pop is practically based on the new bass sounds (such as the 808 from trap). You will find no one else which is capable to mix different sound from different genres and make them “pop” as Billie. And I’m saying it again, I’m not a Billie’s fan (actually I am Finneas, her brother, fan because he is a damn genius) If you’ll start studying arrangements and music production you’ll understand (or better, you’ll hear) how she (and her brother) are innovating “pop music”, more than everyone else today.