Yes modern AIs have an entire opening database and generally have cached the first 20+ moves of the game (for most common openings) from a database of very deep searches identifying the best move. This is absolutely a form of opening prep for AIs.
That said, even without that database a modern AI will completely topple the best human at every common chess variant. Humans cannot defeat modern AIs in chess like games.
Yes modern AIs have an entire opening database and generally have cached the first 20+ moves of the game (for most common openings) from a database of very deep searches identifying the best move. This is absolutely a form of opening prep for AIs.
That said, even without that database a modern AI will completely topple the best human at every common chess variant. Humans cannot defeat modern AIs in chess like games.