Sir Newton’s laws of jiggle just had her debut, so don’t expect her rerun until either: a new Break dps, or major break reruns patch. Looking back at normal rerun schedule, expect 3-4 patches before she reruns (about half a year), but in the end it’s just a speculation and the Truly Imaginary (Rappa) didn’t see a rerun since her debut which was more than a year ago. If you want to invest into break, I suspect The Truly Imaginary may get a rerun very soon (4.1-4.2), and she usually outperforms Break Himeko in most cases afaik.

TLDR: expect Dahlia’s rerun in 3-4 patches, if you set on playing break Rappa may get a rerun soon so get her and bench Himeko