I honestly think it's https://godotengine.org/features/, though I do think the GUI-only WYSIWYG creation flow hits a brick wall a little earlier than Flash did. Lots of content being made with it though!

https://docs.godotengine.org/en/stable/tutorials/animation/i...

If you're being honest with yourself, not even close. Maybe if you Frankenstein Blender for asset creation and Godot/Unity for scripting, but it would be just as much of a monster as Shelley's.