A significant strength of science is that it allows one to make predictions, often with astonishing precision and accuracy. You have yet to convey what the real problem is with this.
No, I asked you to provide evidence that your description of time exists - that's it's something that requires a medium. The underlying concept you used to deny the existence of time. I want to know how time would require a medium, were it to exist. Because otherwise this is just the straw-man fallacy.
Who is "we"?
Mainstream physics has a perfectly good explanation for why someone would begin to orbit if they traveled fast enough, and it doesn't involve concluding that gravity is an illusion.
Years are just part of a reference system. All measurements are made in reference to some standard. they are all human concepts, so this isn't a mark against time. There is a standard meter, there is a standard kilogram, a standard ampere, a standard Kelvin...