tbh, the phone app isn’t the best for it, it works, but I find it’s better on a PC.
Go to segment explore, zoom in on an area, and take the wee slider so that it is only descent segments, then click on the segment, the date of say the KOM’s ride and you’ll see his ride. He may or may not have his GPX there, if he has, you can grab it and load it up on a device, or use summit like Strava GPX app to grab it.
The other way to do it is go ride the area, and while you are recording the ride on your phone, look at the satellite map and navigate to segments.
I’m sure there are better ways of doing it, but that’s how I do it, most of the time.