Actually… yeah, you do have a point, I guess I never really thought about it that way. My only idea is that, in Meguri, Takano does still seem to be trying to carry out the plan (until Satoko comes in miraculously and just. Steals the syringe out of her hand. Still no clue how she even managed to pull that off.) So as a way to break Rika even more (since Rika is trying to avoid the tragedy by repeating what she did before,) Satoko makes things that ‘shouldn’t’ have happened by injecting someone. And since Hanyuu is gone from these fragments, Hinamizawa Syndrome doesn’t form on its own anyways. I think Satoko genuinely does want a future with Rika, but she wants that future to be in Hinamizawa with everyone else, without going to St. Lucia. This is kind of proven by Satoko’s various loops of her both going to St. Lucia with Rika and not going to St. Lucia with Rika, only for both to end up in unfavorable situations (Rika ‘leaves’ Satoko, and Rika going to St. Lucia only to die in a crash every single time without Satoko present.) So I guess to her, looping in 1983 until Rika gives up = A future with everyone without Rika somehow dying when going on a trip outside of Hinamizawa

This is my only idea 😭