So here is my definition of art and beauty. Art is that which is created to the purpose of leading its audience to a deeper and more visceral experience of their own existence. Beauty-in-art is the extent to which the object succeeds in its purpose. Beauty-in-nature is that which is uncreated, but which also brings the experiencer to a deeper engagement with themselves and the world.
Any further refinement is reductionist and exclusionary. There will never be consensus that such-and-such an object is beautiful and any attempt to create a set of conditions for beauty is an egoistic assertion that what I like is “real” art, and what you like is not.