“Any higher frequencies and you burn the tissue – any lower frequencies and the structures become too big”
And there’s where you’re making the implied assumptions. Higher frequencies burn our tissue because our biology is based on hydrocarbon chemistry, where the bonds dissociate at UV wavelengths. A lifeform that had a different chemical basis might not be bother by UV.
Similar with IR, lower frequencies aren’t very useful for vision on Earth because at about 300K, most matter emitted light in the IR range. But if they come from a planet that is a few degrees different, the wavelength emitted by most matter would be shift. We also probably don’t perceive IR because we evolved from sea creature and water absorbs IR frequencies very well. Beings that did not evolve underwater, or evolved eyes after their underwater phase, might not have that limitation.