This guy somewhere in the video says it's 1080p on X and not 4K. So clearly that's coming later down the line. Either way, this is a video worth watching.
https://youtu.be/BWEwqfHx4-Q
Framerate after landing looks very smooth as well.
It is definitely more than 1080p, just look at my screenshots, this stuff is clearly downsampled from higher resolution, no question about that.