Think of the universe as a painting. There’s the image made in paint, and the surface it was painted on. The canvas.
The stars, the planets, the gasses, the matter and energy and even the space between are the paint. What’s the canvas? Is there a canvas? Would the canvas follow the same rules as the paint?
I believe what you are looking for is spacetime which is the foundation that all of the universe exists on. My layman’s understanding is that objects with mass “curve” or “bend” spacetime around them and this is actually how gravity effects objects. An object moving along a straight path (from it’s perspective if on a small enough scale) which is actually following a curved path of spacetime will move in a curved path.
This gives a visual representation of the curving of spacetime.
This shows how a super massive object like a white dwarf or black hole distorts and eventually “breaks” spacetime.
This video also shows it visually fairly well.
