From Renpy to Unity? Would it still be in a kind of visual novel style like it is now?
I've seen others do that and it seems to work pretty well. Like Out of Touch moved to Unity a while ago and it works pretty well. They're still doing the visual novel style too.
If you find Unity is easier to mess around with compared to Renpy, then I say go ahead and do it. I know Renpy seems to be fairly finicky with what you can and can't get away with. While Unity is way more open.