The "best" weapon ultimately comes down to personal preference and playstyle. The Giant-Crusher reigns supreme for pure, uncomplicated damage. The Greatsword offers the perfect blend of power and practicality. The Ruin Greatsword provides a world-ending skill for those willing to make a small stat investment.

Whichever you choose, remember that in a world of Elden Ring Items cosmic horrors and divine tyrants, there is a profound, simple satisfaction in walking the path of Strength—meeting force with greater force, and shattering the foundations of the world, one colossal swing at a time.
https://www.mmoexp.com/Elden-ring/Runes.html