If the person in question is notable, you should create an item.- shouldn’t a manually unmatched item be created directly on Wikidata (after all DBI is all about notable individuals who would easily pass Wikidata’s notability threshold for biographies)
You can use P1889: "different from" (https://www.wikidata.org/wiki/Property:P1889)- shouldn’t the relation between Giulio (Cesare) Baldigara (Q1010811) and the newly created item for Giulio Baldigara be explicitly represented via a not the same as property, to prevent future humans or machines from accidentally remerging the two items based on some kind of heuristics