It's very CPU intensive. Monitor the loads and you'll see.
You should not judge the game's performance from the tutorial missions. They're set in closed, special zones that has nothing to do with the rest of the game.
Come back after you reach Fort Tarsis and do more missions from there.
It really is. This is the first game that made me want to upgrade from my i7 4790k. My usage is consistently 70-90% and my 2080 ti is definitely not being pushed to it's full power. Literally never had a game so cpu hungry before. I'm excited to see the difference with my 9700k whenever ups actually delivers it.