It seems that disambiguation pages are "deprioritized" in the suggest list. When creating disambiguation page (transcluded __DISAMBIG__), it suggests many WD items, except of the disambiguation item itself.
It might be difficult to implement, but I suggest for these cases to prioritize WD disambiguation items.
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Open | Feature | None | T360187 Limit searches to only applicable item types (e.g. humans for Wikisource author pages) | ||
| Open | None | T409263 AutoSuggest for disambiguations |
Would it be a rule to say that any page with __DISAMBIG__ (or equally, with a disambiguation page property) should then not use the normal Wikidata search but instead only look for "instance of" = "Wikimedia disambiguation page"? A disambig page shouldn't be linked to any other sort of item, I think.