What about copy pasting functions and make variants? With a hint in the name about what the variant does?
Copy pasting and modifying seems like a safe low effort working solution.
Is this considered bad practice?
Yes. It's not a bad first-pass, but it can easily lead to problems if there are too many instances of it. In particular, if there is any error in the initial program that's gone undetected or any change to the requirements that it implements, then you have to fix every single copy. Good luck.