There's a philosophical question here, which is that as science and technology get better and our ability to measure things improve, the hidden externalities become less and less hidden. Nobody told Grok the caveman not to burn sticks in his cave for warmth, out of concern for releasing CO2 and particulate matter; but nowadays it's frowned upon to use a wood pellet furnace instead of electric heat, for example.

Existence itself is an externality, since everything any living organism does affects every other living organism, however minutely. There probably exists some amount of externalities that we have to choose to ignore.