Grant and Sherman were competent soldiers and understood strategy. But they outnumbered the Rebels so greatly that they could repeatedly split their army in half, leaving one half in position facing Johnston, and taking the other half along to outflank him and force him to retreat. Good strategy, but they couldn’t have done it without the greater number of troops that they had.

And every Union general in the same situation previously had failed to make any progress on winning the war. Grant knew what his advantages were, and what his weaknesses were. He pinned Lee and forced a series of engagments while Sherman destroyed the Confederacy’s will to fight. Sherman didn’t have overwhelming numbers, BTW.

Every (good) strategy is based on using your strengths and denying the enemy his. It wasn’t “easy” for Grant because he had numbers. If so, the war should have been over before Grant ever got done with Vicksburg.

Other generals had won some battles, but that’s tactics. Grant focused on winning the war. He didnt’ let Lee dictate when and where battles would be fought, Grant forced action on his agenda. Sherman didn’t worry about bad press or unkind references for making life difficult for the people at the ideological heart of the Confederacy.

Of course, Lincoln famously supported Grant because he fought, and the latest POTUS from Illinois doesn’t quite have the same point of view, but wouldn’t it be nice to have a couple of generals like that running the war today? Bah, we have the Copperheads running things.