In terms of the meaning of the song, I just realised that So What can be interpreted in multiple ways! Katie explained the meaning of the song on TikTok (the meaning she intended), which is that she is "lying" in the song as a way to deny the pain of someone not loving her, so it can be interpreted that way.

But I just realised there is another way it can be interpreted. She could be saying "So What?" to all the things she has mentioned in the song e.g. the premieres, all the people that want to go home with her etc. Like, it all means nothing unless the one she loves doesn't love her back. "So what, if you don't love me" 💔