One of the best Ripperdocs that operates in Cyberpunk 2077's Night City is Fingers, aka Finn Gerstatt. He runs a store in Japantown, located in the Westbrook District. While you will visit the vendor during the beginning of Act 2, unlocking him as a usable vendor requires you to finish Fingers' questline. You will need to reach the "The Space in Between" quest, which involves this Rippledoc. He will become available again after you finish his questline, provided you did not anger him during the "The Space in Between" and "Disasterpiece" quests.
https://screenrant.com/fingers-ripperdoc-location-cyberpunk-2077/