After watching the video in high resolution, it doesn't look particularly great. I would guess the game uses upscaling, from an estimated 360p base resolution, and the framerate looks like 17-25 fps. If that can be judged from the video...
Ugh... I don't know, but assume if they had chosen another engine than UE5, it would probably look better and run better. I mean it looks like they are now trying to press UE5 into every little hardware device, and can only make that happen by making the game ugly.