Kejelcha doesn't yet have anything like the championship record of Mo. But he has a much better start at his age, whether that be 21 or 25-27, which is more likely, I think, and he is faster than Mo already at mile, 3000, 5000, and half marathon.
However, Mo's best 1500s are still faster than Kejelcha's equivalent from the mile race. I assume Kejelcha is going to crush Mo's best 10000m time as well. I would not be surprised with the 59:17 half and 12:46 5000m already to see Kejelcha run in the 26:20s, if not even a world record. To be better than Mo, you have to compete with the major championships. He's already faster at almost every distance.