yeah i think the teaser is just from like the first hour of the movie, based on the plot leaks I'd expect the second half to be WAY darker but we'll see
official description:
The film finds Thor (Chris Hemsworth) on a journey unlike anything he's ever faced — a quest for inner peace. But his retirement is interrupted by a galactic killer known as Gorr the God Butcher (Christian Bale), who seeks the extinction of the gods. To combat the threat, Thor enlists the help of King Valkyrie (Tessa Thompson), Korg (Taika Waititi), and ex-girlfriend Jane Foster (Natalie Portman), who — to Thor's surprise — inexplicably wields his magical hammer, Mjolnir, as the Mighty Thor.
Together, they embark upon a harrowing cosmic adventure to uncover the mystery of the God Butcher's vengeance and stop him before it's too late
Dr. Strange comes out in a few weeks in May and Thor 4 comes out in July so in theory they should flow together but I dunno, all these new MCU movies (outside Spidey) feel utterly disconnected from each other with zero build up towards anything.