This gamemode

This game mode is so damn RNG based and just doesn't make any sense how other's get they're lvl 3's but I never come close, and when I do it's always one champ away from leveling them up, and of course I never get it. The items don't exactly say ad or so so I never know if it works for who. And some how I'll be winning a lot early on but as soon as stage 3 or 4 hits I'm losing every battle and getting the items I need, never happens. This game mode makes zero sense, and I just don't what it is that's going wrong, and don't know how people are having fun with this thing.