So I have a theory about Black Bathing Suit.
Insiders have described it as an invite. Knowing that it follows Arcadia, I could see it being a metaphor for how she feels she has to censor her body. The black bathing suit could be the censor box we often see in television and this song could be her urge to rip off the black bathing suit and be free in her body and a big fuck you to anyone who has anything bad to say about it.
The way Arcadia ends/the trio interlude makes it seem like she’s just getting started in terms of talking about her body.
Just a bit of speculation while we wait for the album but I would love if she went in this direction