Is "Guanches" a bad word now we are replacing with "Canarian"? So far as I know the latter term is for modern people of the Canary Islands and the former is a clear term not "early Canarians" "the first Canarians" etc as used here
But apparently there's more to it: in the language the term comes from, it specifically means person from Tenerife. So yes, we might consider it respectful to not refer to people on ancient El Hierro as Guanche. You might want to take a look at how es.wikipedia is linked from en.wikipedia. As a tourist to Tenerife, I didn't know about the nuance myself, before today's wiki dive.