Grant used what he had to maximum perfection. His 6 week overland campaign had heavy losses but not nearly as many as if the war had continued. Ultimately he saved lives. Those are the hard decisions a great general must make. And Lee had a higher percentage of casualties. When brilliant tactics were called for he used them. His Vicksburg campaign was the greatest tactical campaign of the war. His whole objective during the Overland campaign was to hold Lees army in place and act as the anvil to Sherman’s hammer. And it completely worked. In every instance he did what was necessary to win.
The point here is that Grant had huge advantages over Lee. If the supporting structures were equal between them, Lee would have likely won.