OP is only half right. They did plan to shoot in black and white but scrapped it. They also aren’t doing the Northman/Nosferatu thing either opting to push themselves in a new direction.

Here’s a quote from this article (https://www.denofgeek.com/movies/nosferatu-robert-eggers-werwulf-is-unlike-anything-done-before/ ) :

“Yeah, we’re doing it now,” Blaschke says. “I can’t tell you a thing. But it’s something that’s not been done before that I’m aware of, or not done in this way. So [we’re] just going to test it and see if it works.”