Setting wise, Antarctica in the OG made so much sense. Remote, surrounded by frozen tundras, and went hand in hand with the film’s brooding atmosphere. I wonder where else a sequel could take place because civilization is fukked if that life-form touches down on any other continent.
It’s hard to compete with the cold isolation of central Antarctica. The isolation and temperature help up viewer anxiety and make even normal life dangerous for the researchers.
It’s pretty essential to making the plot believable because of the almost complete lack of life out there, and the cold acted as a prison. There’s nothing that the thing randomly can find, assimilate, and imitate. It’s only escape was the researchers or their sled dogs. Their only escape was killing the thing.
I tried to think really hard about your question and how other settings could be possible. I first thought of an ocean platform or submarine but it’s too implausible for it to not be able to escape and find life nearby, over the course of a whole movie.
I think the only believable place would be a space station (for the past, present, or near future setting) or a research base on Mars, our moon, one of Jupiter's moons, or some shyt like Pluto (near future or distant future setting). We know extreme cold slows it down and extreme heat hurts/kills it.