Spotify recommendations are biased because user incentive and theirs don't align. They pay different royalties to different artists, they optimize earnings. Also, they take money to promote music and shove it down your throat.
And, they're starting to push AI music into recommendations, as well. Their incentives are not aligned with users or artists. The major labels were previously pretty OK with the situation, as they had a negotiating advantage against indies and could get better deals for their catalog, but I guess they'll come to regret that deal with the devil.