Full Resolution You can see here the fundamental difference between the Pluto flyby and Arrokoth. Here we're at K-3 days, and the target is still a tiny dot. Here's we're summing 9 high-resolution frames, and Arrokoth is completely undistinguished from the background stars. (Of course, we know which pixel it is because we see it move.) It's one pixel, and it's faint.
At this time during the Pluto encounter ('P-3 days'), Pluto was already more than 100 pixels across (10,000x larger by area!), and we were practically counting craters and doing geology on it. Arrokoth is tiny, and dark, and further out, and moving more slowly, and we don't know its position well -- a far harder target to get to than Pluto.
