[gk1]

There actually are practical algorithms for finding approximate nearest neighbors (ANN) at large scales. Some of them are open source like HNSW [1] and Faiss [2], and some are even offered inside managed services like Pinecone.[3]

[1] https://www.pinecone.io/learn/hnsw/

[2] https://www.pinecone.io/learn/faiss/

[3] https://www.pinecone.io/