A new The Terror? The one that came out some years ago was incredible, and very under-discussed I think.

The first one, the one based on the book, was great and did fly a good deal under the radar. But definitely one of those ones with a core fanbase that evangelized for it and good critical notices. Elsewhere in this discussion Jared Harris's role in Foundation has been mentioned; he's a major, consistent, and excellent fixture in The Terror.

Since they used the book's story already, they made a turn for the series to be an anthology of loosely thematically-similar stories (think American Horror Story). The basic setting of season 2 is Japanese internment during World War II in America, and it's from different writers than the first, and of course isn't adapting the novel anymore. It was much less popular both in terms of viewers and critics.

I'm a little surprised they think the brand still carries enough power to put another original story in there under its name for a season 3. It's also a bit of a double-edged sword: you do get name recognition and some built-in initial audience, but you're also taking on expectations and baggage from the original. This is a factor in season 2's tepid reception, and there have been other similar attempts to slide something unrelated in under an existing banner that backfired: True Detective Night Country comes to mind.