UI I use for Godot-based VNs, trying to support the same keyboard shortcuts that Ren'Py supports. And a very basic example VN made with it. To have more sprites at once you probably want to do some programming, in fact, you'll need programming for pretty much anything, but I think it's more or less easy to figure out what does what.
Based on my VN Sheep Monologue, but replacing the assets (while keeping a few references to it in the text used in the example script).