That is an enormous effect. Dimorphis was 560 feet in diameter. It was about the size and mass of the great Pyramid at Giza. If it hit the earth, it would completely destroy everything within a 10 mile radius and creat earth quakes that would be felt up to 1000 miles away. It would be worse if it hit water as the tsunami effect would flood nearly 70% of the globes ocean coast lines, killing an untold number.

If we can redirect something that size, then it should scale upwards from there. Just need to detect it early enough