The “Prefix Parameter Names” option is not adding the prefix, making other functions with the same parameter names to be unified, like a texture input is being the same to all the textures, because the parameter(variable) is the same name in the all the material functions (I don’t want to change manually as it is too much).
These 2 Functions has the same exposed variables(parameters) names, because of that, they are unified, I want to separate them.
Assuming you are the person asking the same question on discord, The option to add the prefix parameter names adds a prefix in the material instance to easily see what variables come from a material function. It does not change the variable names.
I also told you that an easy way to do this is to copy the nodes in a material function into a text editor, rename the variables there, and paste them into a new material function so you have a new identical material function with new variables.
Alternatively (which I also explained) is to expose these variables from the material function into the material, set one up, copy these, paste them into a text editor, rename them, copy them, and paste them back into the material so you quickly can add the new variables.
Additionally, a LOOOOOT of gamedev revolves around annoying repetitive tasks that in some cases can be days, weeks, or even months (The cape in the first batman arkham game took one person almost the entire production time to finalize) You might want to consider being more positive towards these annoying repetitive tasks because you will be facing a lot of it in your game development career if you wish to pursuit it.
Having said that, I do agree that it would be great to have a feature in material functions that allows for variables to have pre/suffixes, either auto generated, or trough a variable one can set trough the material function via a variable or other way. Sadly at the moment that is not a thing.
Keep at it and good luck! you’ll get the hang of it soon!
Hello Luos, thanks a lot for your answer, you’re right, now I understand the copy and paste you mentioned, really great technique!
that pasting to text editor trick is very useful! a true life saver! thank you very much 
i agree about what you say about repetitive tasks and thats exactly why asking for features that reduce those tasks or make them less repetitive makes the engine better and our work easier.
being not very positive towards annoying repetitive tasks is the mother of invention and change
For anyone wondering how to do this easily / en masse:
Maybe you can do it a fancier way with code but this worked for me. A great trick, Thank you Luos!
Thank you so much, @Luos !! This made creating unique material functions SO much easier. By copying and pasting all the nodes into a text editor (I used Notepad++) and using the Find and Replace features, I could instantly replace parameter names, group names, and even comment titles. Super useful! 