Wikipedia current has a debate on whether the Copernican system was heliocentric. See the Talk pages for Nicolaus Copernicus and Copernican heliocentrism.
This is a diversion from the usual Copernicus argument, which is whether he was Polish or German. He is customarily called Polish, but nation-states were not well defined, and there is an argument that he was more German than Polish.
The main point of confusion is that Copernicus did not really put the Sun at the center of the Earth's orbit. It was displaced by 1/25 to 1/31 of the Earth's orbit radius.
It appears that the center of the Earth's orbit revolved around the Sun, but you could also think of the Sun as revolving around the center of the Earth's orbit.
So is it fair to say that the Sun is at the center of the universe? Maybe if you mean that the Sun is near the center of the planetary orbits. Or that the Sun was at the center of the fixed stars. Or that the word "center" is used loosely to contrast with an Earth-centered system.
In Kepler's system, and Newton's, the Sun is not at the center of any orbit, but at a focus of an ellipse. It was later learned that the Sun orbits around a black hole at the center of the Milky Way galaxy.
I am not sure why anyone attaches such great importance to these issue. Motion is relative, and depends on your frame of reference. The Ptolemy and Copernicus models had essentially the same scientific merit and accuracy. They mainly differed in their choice of a frame of reference, and in their dubious arguments for preferring those frames.
People act as if the Copernicus choice of frame was one of the great intellectual advances of all time.
Suppose ancient map makers put East at the top of the page. Then one day a map maker put North at the top of the page. Would we credit him for being a great intellectual hero? Of course not.
There is an argument that the forces are easier to understand if you choose the frame so that the center of mass is stationary. Okay, but that was not really Copernicus's argument. There were ancient Greeks who thought it made more sense to put the Sun at the center because it was so much larger than the Earth. Yes, they very cleverly figured out that the Sun was much larger. There is a good logic to that also, but it is still just a choice of frame.