Unity games aren't editable like Ren'Py games, so there's nothing you can really do without some proper hacking AFAIK. Unless the game creator allowed for some sort of scripting on top of the engine, which is unlikely for this genre.
More specifically, Unity games don't follow a particular pattern like RenPy does, such as some specific, set variables and whatnot. You can't just pop a file into Unity and expect to be able to change a character's name or whatever, because that game might use its own code to make a VN, so you'd have to know that code specifically and target it. It's practically impossible to make a "universal" Unity mod that has a lot of the same high-level functionality that URM has, just because of that variation and the nature of Unity as a game engine. A Unity game can be anything, anywhere from a VN to the next Fallout NV, and because of that fact, no Unity mod can be as universal as URM.
However, Unity games are editable like RenPy, if you're willing to use/learn BepInEx, MelonLoader, or any similar modding framework. Those are just easy-to-install modding frameworks that hooks into Unity games and allows certain plugins to be ran, such as
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or even
my mod for Femboy Survival.
TL;DR: Unity can be as moddable (if not more) as RenPy, but there is no plug-and-play, "universal" Unity mod that functions like this one, especially not if the Unity game is a VN.