Hello, I am having a similar issue. I am using multiple textures on a shader that I am creating. I have attached two screenshots of one of my textures. You’ll see that the texture in Photoshop is of decent quality. But when I bring it into UE4, the resolution seems to be a lot lower. I saved the image from Photoshop as a 32-bit targa. The image you see is also just one channel. I packed multiple images into the R,G, and B channels of the texture.
Any help is greatly appreciated.