I think it’s time to get past the idea of “truly intelligent” and recognize that there are many varieties of cognition that differ in how they are embodied. Peter Godfrey-Smith’s book, “Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness” is wonderfully enlightening in that regard.

You are right that to understand many things the way we humans do, artificially cognitive systems will need senses and effector organs similar to ours, but many other systems can be quite “intelligent” in their ways with very different senses and effectors than ours.