I struggle to believe you didn’t see the “main” villain early on. I’m not sure spoilers are allowed but it became obvious to me when the mayor looked at an old photo of that fanatics family. It immediately clicked for me who was the odd one frequently showing up in every episode.

It took me longer to guess who the monster is as i initially guessed correctly until something happened to allegedly put the suspicious character and a monster in one scene; so I thought “nah my theory is proven wrong”. Until it wasn’t.

Tbf I didn’t like the last episode as much as well but only due to Wendy’s manner of confronting suspected killers with almost no back up plan (“please surrender, you have been exposed”).

So yeah, I’m sorry you missed the clues, doesn’t make the final villains “unassuming” and forced.

Also the guy who was initially arrested was shoved in our faces so hard, it was so obvious, anyone who ever read a detective or played a detective game knows it’s NEVER an obvious one.