You’ve already identified one of the key benefits of splitting this information into separate documents - if multiple authors are updating different sets of information in the same doc, it can be useful to split those sets into different documents to avoid unnecessary conflicts.
Using separate, smaller documents will also generally reduce the amount of data being synchronized when only a subset of a larger document is being modified. Delta sync accomplishes the same thing, but you’re correct that it’s preferable to use smaller documents.
What you may want to be wary of is using many small documents that are all frequently changing. There’s some replication work associated with notifying the replicating peer about a changed document - this includes document metadata (key, revision, sequence). So replicating the same information in 100s of small documents is going to have more replication overhead than a single large document.