Non-factor in patreon support - ok, point taken.
But rescaling UI's in unity should be automated by the game engine cuz if their ui's were set in a fixed size pixel rather than by percentage of the screen res, then it's not a good game engine imo. As for the images... What image size do you use? Old Renpy porters usually don't bother sizing down the images, no biggie, except that of course it's a memory/storage space muncher, but it'll draw nonetheless (with a bit of hiccups hereand there) cuz it's just a texture that will fit itself in a 2d rectangle if that's how renpy works.
Edit: about the ui rescaling, yeah... They have to be re-edited for small screens silly me