How do I make a basic Game.ini mechanics adjustment into a mod like Epic Level?

I am not 100% on this answer, but, i can say with fair certainty, editing/changing user files on the local machine (read: outside your mod folder) could fall into some serious issues.
I do not believe this is something supported by ADK or Epic in any way shape or form. You would have to setup a mod for difficulty level that mimicked the “game.ini” settings changes.
If you try setting game.ini settings from a mod, thus editing outside the system you have rights to edit, i think you maybe treading on some serious unstable areas.

Maybe someone with some more exp in the field of ARK can chime in, but, that’s a pretty general answer.