Stockfish 8 actually won games against Alpha Zero. But Stockfish 11 (which is still classical evaluation engine with no neural net support) totally decimates Stockfish 8, and Stockfish 13 (which uses neural net) totally decimates Stockfish 11. Stockfish 14 just got 30 elo points stronger than 13.

As it stands now, Stockfish 14 is the strongest chess entity humanity has ever seen.

The NNUE evaluation was first introduced in shogi, and ported to Stockfish afterward. It can be evaluated efficiently on CPUs, and exploits the fact that only parts of the neural network need to be updated after a typical chess move. The nodchip repository provides additional tools to train and develop the NNUE networks. On CPUs supporting modern vector instructions (avx2 and similar), the NNUE evaluation results in much stronger playing strength, even if the nodes per second computed by the engine is somewhat lower (roughly 80% of nps is typical).