Artnet has been doing the same basic analysis (finding comparable artworks and calculating the worth of a piece of art) for over a decade. They offer theirs as an add-on to their price subscription service: https://www.artnet.com/analytics-reports/
Thanks for reading, Artnet is awesome. To my knowledge they do not have a database looking at all known works by artists, they focus on works sold at auction. This makes sense as they cover much larger group of artists and info on complete works is typically not available for the majority of artists.
Yes – I think the point of sticking just to open auctions is so that the prices and indexes they have represent what the market thinks of an artist and particular works.