> My conviction is the complexity of chess is not as high as we think, and that there exist a neural network of less than 10B float32 weights which can encode perfect play

Given the number of possible games (numbers above 10^80) you would need EXTREME sparsity to encode it in less than 10B / 10^10 params. Sounds information theoretically impossible to me ¯\_(ツ)_/¯

Leela Chess Zero has hundreds of millions to few billion parameters AFAIK.

The argument about the game being finite and thus solvable is misguided IMO.

AES encryption is also finite, and you can enumerate all possible combinations, but not before the end of time..