I’ve never heard the term UX icon used before, but I like to differentiate between single-color UI icons, used to add meaning to UI elements, and illustrative icons, which are often multi-color and tend to be more decorative or superfluous.
Ah I was being a little facetious, sorry - I am fascinated by the compulsion to always say "UX & UI" or "UX/UI", as though they are inseparable things and not different words/ideas/concepts with different meanings.
tl;dr - it's plenty fine to just say "icons" in this case, the Noun Project