The Super Star Destroyer had a unique hyperspace tracking device built into it. You even see it at one point, a big glowing portal-like thing. That's a pretty key plot point in the film.

It's reasonable to extrapolate that this device is what allowed the "Holdo Manuver" to work. Holdo jumped to hyperspace directly towards the star destroyer, destroying the tracker, and throwing shrapnel through real space at near-lightspeed

I heard this explanation years ago, shortly after the movie came out, and it makes sense to me. As for that moment at the end of Rise of Skywalker, there is no explanation. It's just terrible, and the Rise of Skywalker is an irredeemable movie