It's kind of surprising to go back and watch Toy Story in 4k today - the rendering really is quite rudimentary compared to what even video games put out now.

But - you have to be paying attention to see it, because Pixar knew the limitation of their systems. For example, rendering of the time made everything look plasticy, so they rendered ... plastic toys as the main characters! The most noticeable graphical issues are with the rendering of people, but those are put in the background.