Yeah, the tone of the movie is really off. Apparently that’s due to studio interference:

The project was difficult for [writer William] Gibson and [director Robert] Longo. After they struggled for years to finance a low-budget adaptation of Gibson’s story, Sony greenlit Johnny Mnemonic with a $26 million budget. When Reeves’ previous film, Speed, unexpectedly became a major hit, Sony attempted to retool Johnny Mnemonic as a blockbuster. Longo experienced extensive creative differences with the studio, who forced casting choices and script rewrites on him. The film was ultimately recut without Longo’s involvement, resulting in a version that he felt did not reflect his artistic vision. Described by Longo and Gibson as originally full of irony, it was edited into a mainstream action film and received negative reviews from critics.

… Longo and Gibson originally envisioned making an art film on a small budget but failed to get financing from the studios.[10] Gibson said they wanted to avoid flashy, MTV-inspired visuals and “plunge the audience into a very strange but consistent universe”.[9] Longo commented that the project “started out as an arty 1½-million-dollar movie, and it became a 30-million-dollar movie because we couldn’t get a million and a half.”

… When Reeves’ previous film, Speed, turned into a major hit in 1994, expectations were raised for Johnny Mnemonic, and Sony saw the film as a potential blockbuster hit.[16] Gibson said Sony executives began pressing them about whether their film had busses or explosions, critical elements of Speed.[17]

Longo’s experiences with the financiers were poor, believing that their demands compromised his artistic vision. Many of the casting decisions, such as Lundgren, were forced upon Longo to increase the film’s appeal outside of the United States. Longo and Gibson, who had no idea what to do with Lundgren, created a new character for him.[18] Lundgren had previously starred in several action films that emphasized his physique. He intended the role of the street preacher to be a showcase for further range as an actor, but his character’s monologue was cut during editing.[19] Gibson said that the monologue, a sermon about transhumanism that Lundgren delivered naked, was cut due to fears of offending religious groups.[20] Kitano was cast to appeal to the Japanese market.[14] Rollins, who is uninterested in science fiction, joined the cast because he liked the film’s focus on an upcoming disadvantaged underclass.

… The studio continued to challenge Gibson and Longo on the script through principal photography, making some of the shooting both tense and confusing.[15] The script was meant to be a commentary on science fiction films and how they are made,[24] and the action sequences were meant to be ironic and reminiscent of scenes that Gibson and Longo enjoyed in B movies.[17] Gibson and Longo had instructed Reeves not to play the character straight.[24] For his part, Reeves said he played the character “very robotic and rigid”, which he found exhausting.[25] Reeves’ suit and tie are a reference to [Longo’s sequential artwork] “Men in the Cities”.[12] When Johnny cries out for room service, this was a reflection of Longo’s frustration,[7] and has also been identified as a reference to “Men in the Cities”.[26] The ending, where the Street Preacher appears to revive, was forced on Longo, but he refused to shoot the scene straight, as requested. The studio approved of his version nonetheless.[17] Eight minutes of extra footage starring Kitano was shot for the Japanese release of the film.[14]

Gibson said that the film was “taken away and re-cut by the American distributor” during post-production. He described the original film as “a very funny, very alternative piece of work”, and said it was “very unsuccessfully chopped and cut into something more mainstream”.[27] Gibson compared this to editing Blue Velvet into a mainstream thriller lacking any irony.[20] Their editor, Ronald Sanders, was replaced by someone that Longo said did not understand the film.

https://en.wikipedia.org/wiki/Johnny_Mnemonic_(film)

There’s a version called “Johnny Mnemonic: In Black and White” that came out in 2022 that’s supposedly a lot closer to a director’s cut, but I haven’t seen it.