Well if you want something that can really do everything...
https://www.konaworld.com/products/process-24
This is what my son has. Its been awesome. He has done everything from riding trails, riding DH parks, jumps, rocks, xc race, Triathlon.....He got it when he was 7, not that he is just turn 10 and a little bigger...I made it into a 26/24 mullet. Commecal also makes that clash that is pretty nice too if you can find one.
Not sure how tall your child is....my son is about 4'7" now....probably going to start looking for a XS or S 27.5....but for now this bike still fits him well.