Don't search by a pure opus or a BWV number then if you search Canzona in D + Insert Performance Details you'll find it.
Never had an issue finding what i wanted, i didn't mind to have to scroll and i treat Spotify's search just as i treat Google's search, the secret to finding stuff on Google is to figure out what the 100000 idiots that searched for the same thing before you actually searched for before ending up clicking on what you really want.
The 1st several results will be SEO's then couple of promoted ones then you'll find something that you can actually use, and Spotify isn't any different I'm pretty sure that record companies pay directly or by accepting lower fees in exchange for Spotify to promote their records, so yep Classical Halloween Bach from the Dead might be promoted, or it might be there because more people actually enjoy listening to it just as most people would probably enjoy TSO's version of Mozart's and Beethoven's works with a nice jam more than some dreadful orchestra from the Soviet days of eastern Europe.
Streaming providers aren't the Library of Congress don't expect them to give you exactly what you look for since they assume like any other search engine that you don't know what you are looking for and they also need to make some money on the side, but if you don't give up and are willing to waste 10 seconds you'll find what you want and then well just hit the bookmark button.
P.S.
If you want to listen to a specific performance why are you searching the work and not the "artist"?
For the most part there will be more performances for a given work than all the recordings a single orchestra can record in it's life time. Want to listen to a recording by Sydney's symphony orchestra? Search for Sydney Symphony Orchestra, click it scroll down till you find it not the other way around :)