Riot Needs To Fix Their team Comp Systems

Recently I was in a game where everyone on my team was not level 30, including myself. During the loading screen, I realized I was the only one on my team with a mastery keystone. Although only the Gnar top lane had a mastery Keystone as well. When we got into the game, Gnar was dominating me in the lane which made me think I wasn't building right or he was doing too much damage. I soon realized that he was level 30 from the buffs he had from different mastery trees, which made me upset because no one in the game was level 30, but him.After we lost the game I looked on op.gg to find that the Gnar was a silver top player who has a 100% win rate in his games. I hope that Riot fixes this problem and helps leveling players and or smurfs with this problem. All I am asking is that Riot fixes their team building systems to where the enemy team, as well as your team, doesn't have any players like this on them. I just want my games as well as others to be fair in the most ways as possible. However, this is stopping that. Please share this if you or anyone else is having these problems in your games.