Duplication can sometimes be useful, for instance if you have many small variations on a central process. Trying to make one process with all the edge cases baked in leads to overly-complex, hard to reason about, expensive software.

In my experience, the right way to handle this sort of situation is to create a functional mini-DSL for the process that handles all the implementation details, then create a "default" process which serves as a template. If a process needs slightly different logic, just copy the template, update the DSL to support any new logic, and update the template with the new DSL statements. This approach lets you give semantic meaning to implementation details, and you can see where all the different custom logic is at a glace by looking at all the template copies. As long as the template is only calling out to DSL actions with no internal logic of its own and process flow is correctly encapsulated in the DSL, you should never need to update templates to change behavior, only update the DSL.