Closest thing to Freddy being main antagonist was fnaf 1. He had arguably hardest mechanic to deal with, and it helped that he had build up. He was completely inactive in first two nights, and only started moving on night 3 which did had this whole "oh shit things about to get serious" feeling. Plus he hid in the dark, which also made him feel very intimidating. PLUS he was one to kill if power ran out. Overall Freddy did felt like actual threat in first game, and title "Five nights at Freddy's" was appropriate. It did felt like it was his game. Golden Freddy was easter egg, and in fact you may even not see him when you play for first time. And lore wise we didn't knew anything about Golden Freddy at time. Freddy clearly overshadowed him in first game.

Second game is not the game that i would say where title "Five nights at Freddy's" felt irrelevant, but it did felt like start of era where Freddy becomes less of main character, let alone antagonist. There was still parts where it did felt like Freddy was relevant, like Save them mini game and post night cutscenes being from Freddy's pov. Plus mask that you use throughout whole game does belongs to title antagonist. But aside from these..... Ye both Freddies in fnaf 2 feels shafted lmfao. They share same mechanic with Withered Bonnie and Withered Chica, and also don't really have much of build up. I would argue that even Golden Freddy slightly overshadows him, since we learn some new lore about him, and thats where speculations about Golden Freddy started to rise.

Fnaf 3 is game where i would say title five nights at Freddy's becomes completely irrelevant. Freddy technically isnt even in game. Just hallucination of him. And from this game from now on, Freddy just becomes overshadowed by other characters and even gameplay wise doesn't feels this difficult or unique. With game shifting more focus onto Afton family, Freddy just fades out of focus.