I am upgrading to a ROG swift.Will textures in game look better or are they made for 1080p?
Yes, but not to a huge extent. Textures in most games (which are usually terrible console copypastas) are of pretty low resolution anyway. Skyrim's default textures are at 512x512.
On a 1440p resolution, it won't look considerably better than at 1080p. There will be less aliasing, because there is greater pixel count and density, which are able to smooth out textures better.
4K textures, however, will look better. I would not say significantly, but they will. It is more of a degree of sharpness than actual texture quality. 1440p will not change the resolution textures are at.