Can you show one large-ish GUI software written in Clojure? Something like, idk, Blender, DaVinci Resolve, Unreal Engine...
If you are really interesting in this topic, check out the following pages: https://clojure.org/community/success_stories
Another big Clojure UI/graphics framework is Quil, which is based on Processing and does an even worse job of hiding it’s imperative/stateful core.
Except for things like React which are more or less functional reactive programming, but in case of react its stateful. Functional reactive programming exist, and GUI is not obliged to be OO