Could you link to one of the entries in the database that you’re wanting to match to? It sounds to me almost like we have the recordings in the database, but not releases that encapsulate them, and all of Picard’s search functions rely on picking out the latter. If you really wanted, you could add the recording itself manually, but that winds up being a bit clumsier even if you just look at the long-term maintenance.
If I’m just misunderstanding things, and there really are 45 releases already in the database, you actually can weight Picard to choosing them: in the Options window, there’s an arrow to the left of the Metadata option – expand that, select Preferred Releases, and tweak things as you want. I’d recommend selecting the format in the bottom section over (or in addition to) dragging the slider for singles to the right because the format is just a bit more likely to have been specified.