Linguistically, whatever they name themselves in their own language would just translate to whatever we call them in our languages because that’s usually what we do. I think this would be especially true if the alien language is physically impossible to vocalize as a human.

Fair point. I was rather thinking about it from more of a human categorisation point of view. If they're not all mechanical, or weren't constructed, I can definitely see some limits with using "mechanoid" as a descriptor.

Like how you could categorise a lot of mammals as organoid, but it lacks the nuances compared to having other words like mammalian or humanoid.