[matt_j]

The way I understand it, light from far away, very far away, is red-shifted because the universe is expanding at every point and the wavelength of the traveling light is stretched. Stretching the wavelength means light from the blue end of the spectrum moves closer to, or indeed, into the red end of the spectrum.

If you want to look very deep into the past, say, 13 billion years ago, any light from galaxies that old has traveled 13 billion light years PLUS however much the universe has expanded and will be red-shifted out of the visible spectrum, so you need an infra-red telescope to see it. Hence, JWST.

You simply can't see these things without using instruments that can detect the right light.

On top of that, everything in the universe emits light across a broad spectrum, above and below the visible spectrum. We can enhance our knowledge of these things; stars, planets, galaxies, etc by using instruments that can "see" infra-red, radio, x-ray, gamma ray and that is additional information on top of what our eyes can see in the visible spectrum.