From what I hear a lot of game engines have horrendous bugs that is terrible for performance (like people straight up using DirectX incorrectly, not being aware

From what I hear a lot of game engines have horrendous bugs that is terrible for performance (like people straight up using DirectX incorrectly, not being aware of the quadrillion performance hacks that AMD/Nvidia are keenly aware of)--so what AMD and Nvidia does is they "fix" the game engine by making it more performant. Potentially it might be better for them to contact the game dev for a collaboration or just to tell them to fix their shit, but it might a) be more annoying than to just silently patch their code b) might benefit their competitor.