@personenkult I would recommend Escoria, as it's based on the Godot game engine, so you're not locked in to the existing functionality in case you want to include new features in the future.
See here: https://github.com/godot-escoria
Otherwise here is a list of other visual novel game engines you could consider: https://gamefromscratch.com/choosing-a-game-engine-for-visual-novel-and-adventure-games/