Talk to them ONCE when they move in, then don't talk to them at all. Completely ignore them. Time Travel day-by-day, everyday talking to every villager that you don't want to move out. After you have Time Traveled for about a week, somebody should ping you and tell you that they want to move. If you get the dreaded " I can't move now, I thought we were friends! " exit the game without saving, do not talk to the villager again. They should move out on the day that they originally said they would.
I time travel until someone asks to leave. Then I time travel two days forward. Then two days back. Someone will ask to leave then and just continue until the villager you want out decides to move.