I'm totally going out on a limb and guessing here - I'm more on the UI/UX side of things so I know nothing low-level about what goes into a building recommendation engine, algorithm, or whatever. But I do know music pretty well, and this feels like it's matching too closely to the technical aspects of the music and not the overall theme/je-ne-sais-quoi that makes a song something you feel.

I tried two of my all-time favorite songs:

The Gaslight Anthem - Handwritten

Thrice - The Artist in the Ambulance

On the first, I would say it was a total swing and miss - the recommendations had similar elements to Handwritten like strummed power chords, but the vibe was completely off. With Thrice, same thing. The first match was a remaster of the song itself by the band, so of course despite being a "different" track it was the closest possible match. The rest of the recommendations had a similar tempo and more heavy metal riffs (as are common in Thrice's songs), but none of them were songs I would voluntarily listen to.

This is a cool idea and I hope OP if you read this you take the criticsm as it's intended - I'm not trashing the implementation or anything. This just feels like it truly is a robot that can't feel the emotion of a song making me recommendations.