“Best” in other words best overall is not a thing.
Peridot had the best redemption arc. Pearl had the best development arc. Lapis had the best relationship with Steven, Garnet was the best character for Steven’s development meaning Best Mom
, Amethyst was the best supporting character for every other plot, Blue was the best intimidating villain, Yellow was the best character for post-Future future exploration, White was the best character for basically being the backstory behind all backstories and thus the series Kevin Bacon, Pink is the best character for AUs and fanfics, Bismuth is the best character for exploring the darker side of the Crystal Gems, Topaz and the Beetles tie for the best characters for demonstrating Fusion (the second most interesting thing in the show) outside of Garnet’s romantic style, Yellow and Blue Pearl have both the best aesthetic and comic, Volleyball is the best woobie and character for diverse fanart interpretations, Alexandrite has the best design, etc