Well, I answered your question about what I mean by understanding at least.
When I consider “intelligence” I see it as implying agency and free will, and yes going hand in hand with sentience and understanding and sufficient shared context.
1. A phrase “highly intelligent non-sentient entity” does not make sense to me. An entity cannot be intelligent if it does not understand symbols it manipulates, and it must be sentient to have that understanding.
2. If you imagine a highly intelligent being with zero shared context with you, it may as well appear as completely unintelligent to you because you have no way to reason about its intelligence to recognize it. For example, we anthropomorphize aliens but truly it’s silly to assume extraterrestrial intelligence would have any shared context with us—so to us it might as well be indistinguishable from a semi-predictable force of nature. Should we treat any force of nature as intelligence then, like we perhaps used to (cf. gods)? Perhaps not, because if anything is intelligent then what use is the word? So we could instead limit the scope of “intelligence” to something sufficiently similar to human intelligence that we can reason about it, and then the word is practical. E.g., an octopus could be intelligent.
Per above, I do not see AI as intelligent in how I understand the word (if I did I would balk at its abuse), I think it’s a tool that cannot see any meaning in symbols it manipulates even if it is very effective at it thanks to large training corpus[0]. Even if it might produce human-like output, I don’t think it is a product of intelligence because it has no free will or agency from our vantage point; and if I am wrong and it has intelligence and sentience, just so different from human’s that we can’t understand it, then for all purposes it might have no intelligence in any useful sense of the word anyway (and a notion of hurting it would similarly not make sense).
If you see intelligence as a word to describe a capable software tool, then we may be in agreement regarding what AI roughly is even if we disagree about what intelligence means or whether it is orthogonal to sentience.
[0] And, seeing as it’s a closed tool operated for profit, we ought to hold its operator responsible for honoring intellectual property belonging to other humans.