for VN's Renpy, not just cuz its simpler but also cuz it works on ALL operating systems outta the box. for sandbox games, its a bit more complicated todo them on Renpy, but I'd still go for Renpy personally because making Unity work on all operating systems is a HELL! (same goes for most other game engines ngl). Also I'd choose Godot over Unity any day, Unity too fat for no reason lol
For AVN - RenPy, you don't need anything more complicated than that. And it's easier to make mods.
But for real games, I prefer Unity. Of course, if the developer has taken care of optimizing the engine.
I realize that my opinion is unpopular, because most people on this forum are interested not even in VN, but in KN, but I'm interested in games, not comics, which in essence KN are.