Process Guide: Concluding Phantom Liberty Ahead of Schedule
Cyberpunk 2077: Phantom Liberty adds a host of big new features, among which is a significant new story for the player to engage with. However, if you're not keen on another extended storyline, you can choose to prematurely end it.
The Phantom Liberty quest allows for a dialogue option where V can simply dismiss the mission. Consequently, you won't be able to proceed further in the task as the other characters decide to continue without V. This nuance added by CD Projekt Red puts a nice touch of realism to the game, but it is not recommended if you've just purchased the DLC.
Regarding roleplaying, it is comprehensible that V would not want to commit to anything that doesn't lead to removing Johnny Silverhand from their consciousness. As pointed out by PC Gamer, this can be done as early as the fourth mission in Phantom Liberty.