Apparently, in the early 1990s, director Larry Cohen was making attempts to bring She-Hulk to the silver screen (via Digital spy). She-Hulk was originally supposed to make her film debut even earlier, in the 1990s TV movie The Death of the Incredible Hulk. However, ABC allegedly shelved the idea to make a solo spin-off film. The director intended to cast actress Brigitte Nielsen, best known for starring in giant blockbusters like Red Sonja, Rocky IV and Beverly Hills Cop 2 in the late 80s (via IMDb). The film was even previewed at the 1991 Cannes Film Festival along with costume tests and promotional photos of Nielsen in what was supposed to be a full suit.
Despite this, the film never got off the ground and was cast aside in favor of other projects. While the final answer to why was never officially released, it is said that the reason was probably finances and performances in other Marvel films at the time. “Howard the Duck” performed terribly among the spectators. “Punisher” almost just as bad in 1989, like “Captain America” 1990s. Things have certainly come a long way, and even in the early 2000s, Marvel began to find its footing in other projects like X-Men. Unfortunately, She-Hulk was delayed until Kevin Feige announced his live streaming debut in 2019 (via Term).