If a Wikipedia page shows two types of items due to being more efficient and logical, then I add the Wikipedia link as well as Wikidata. Most singles are not important enough to have separate Single and Song pages. This new split of Song and Single seems to be a strange pedantry drive at Wikidata without thinking things through fully.
One of the problems is a Wikipedia page only has space for a single Wikidata link. Currently this is wrong. Wikipedia is breaking the one to one mapping between itself and Wikidata.
A similar issue happens with Film Soundtracks. Often they are placed onto a Film’s Wikipedia page. I end up adding those to MB Annotations