The greatest wrestlers of the 1990s were "Stone Cold" Steve Austin and The Rock in WWE, as well as Sting in WCW, but if you had to choose one, Stone Cold Steve Austin is often considered the greatest.
Main reasons:
Major popularity and influence: Austin is an icon of the "Attitude" era in WWE, when the company experienced an incredible surge in popularity. He became the face of the changing style of wrestling, from a family show to a more mature and action-packed one.
Feud with Vince McMahon: The story of Austin's feud with WWE boss, Vince McMahon, is very famous and has attracted the attention of many fans. This story not only helped Austin become a superstar, but also saved WWE from bankruptcy and allowed him to win the ratings war with WCW.
Anti-hero character: Austin brought an "anti-hero" figure who did not obey the rules and often went against authority, something that audiences really liked at that time. The catchphrase "Austin 3:16" has become one of the most iconic.
Achievements and championship titles: Austin won many titles, including multiple times as WWE champion, and also won the Royal Rumble three times (1997, 1998, and 2001), which is still a record.
The Rock also made a huge impact with his charisma and promotional abilities, but Austin's dominance and influence in that era was hard to match.