Approaches

NNUE evaluators

A small neural network, cheap enough to run at every leaf of a search, that judges a board from its cells.

Give every cell a learned description and predict the game's remaining lifetime. Good predictions still did not produce good choices.

Judge the board at the moment just before the next disc is dealt, so the value never has to be split seven ways.

Let a small learned board evaluator decide where a deeper search should spend its time, while keeping the exact search as a safety net.