Rey and Finn had almost the whole movie of The Force Awakens to establish a friendship, which they did as quickly as he did with Dameron, and we actually got to see more of the Rey-Finn friendship develop in Force Awakens. They were separated in The Last Jedi, but Rey's name was the first one out of Finn's mouth when he woke up in The Last Jedi and she was very happy to see him, that hug they shared had feeling. I buy Rey and Finn a lot more than Rey and Ren, a man she saw murder Han, etc. or Dameron, who she just met at the end of The Last Jedi.
Boyega and Ridley have chemistry, and Finn and Rey should be together romantically. They won't be, but they should be. Their characters have an easygoing, back-and-forth that Rey doesn't have with Ren or Dameron.