the people who believe in the round earth never change their theories
I guess that's exactly why you guys have no working model of gravitation and are actively pursuing a new one.
This is a most telling show of total ignorance about science. A
model is what you need to make
predictions, which, if verified through experiments and observations, is the basis for a theory. And we are full of verified predictions with both Newton's model and Einstein's model of gravitation.
If you want to decry all of modern science you can at least learn what the scientific method is. Whether you like gravitons and space-time or not, they are not there for your amusement, they are there to make predictions and therefore qualify perfectly as working models.
What you really want to see is not called a working model, it is called a layman's explanation, the kind that makes you say "wow, now I understand!".