For instance the tale about sharpening his cleats is now believed to be a myth. Cobb certainly was fierce and not well liked by many, but he also had friends among baseball's elite at the time. Most of the stories originated from a discredited author who wrote his bio after Cobb's death.
From Wiki:
A noted case is the book written by sportswriter Al Stump in the months after Cobb died in 1961. Stump was later discredited when it became known that he had stolen items belonging to Cobb and also betrayed the access Cobb gave him in his final months. As a result of the movie Cobb, which starred Tommy Lee Jones, there are many myths surrounding Cobb's life, including one that he sharpened his spikes to inflict wounds on opposing players.
Also, Cobb's views on race were more complicated than have been portrayed:
"Cobb's father was a noted advocate for racial equality.
Cobb told the Sporting News in 1952 that "the Negro should be accepted and not grudgingly but wholeheartedly."[150] In 1953, black newspapers cited his praise for Brooklyn Dodgers' catcher Roy Campanella, who Cobb said was "among the all-time best catchers" in baseball. ... In the obituaries that ran in the black press following Cobb's death, he was praised for "[speaking] in favor of racial freedom in baseball."
Regarding the myths:
https://www.vintagedetroit.com/five-myths-about-ty-cobb/