Stockfish and other classical engines were never intended to be run in matches without opening books (of which there were plenty). Development assumed the presence of opening book and authors made 0 effort to make engines play well in openings because of it. This is also the reason classical Stockfish was a very small binary. A little effort to make it even by including even a very small opening book (like 50MB or something that would result in still smaller binary than NN engine with its net) would make it much more interesting.

The result was that Stockfish lost many games by walking into known bad lines and lost way more games than it otherwise would.