There is another issue which hasn't been addressed, namely that the negative might either be out of focus or diffraction within the image itself. While the grain is evident or prominent as you say, that is referring to the silver grain of the physical negative and not about the image on the negative. What was the f-stop of the image you took? If it was f16-f22 on a 35mm camera, no amount of darkroom manipulation will make it sharper than what is inherent in the negative itself. The focus enlarger can tell you want the maximum sharpness of the negative is, not what the sharpness of the image is.