Remove Shutdown Experience.

Shutdown xp works like this: the amount of experience you need to level up from your current level to your next level, plus 7% of that exp for every level you're ahead of your killer. EXAMPLE: after demolishing Vayne in lane, you are level 7 on Caitlyn, and Vayne is level 5. Vayne requires 1700 xp to level up, and you require 3200 (stats are all cited below). You get ganked by the enemy jungler and Vayne gets the kill or assist; it doesn't matter for the example because assists grant FULL shutdown experience. Because of the kill/assist, Vayne gets (50 + 7 + 7 = 64%) of the experience you need to reach level 8. 64% of 3200 is 2048. So Vayne just levels up and then some from getting that assist/kill on you, and that is in the best case scenario; usually people aren't in a position where they are exactly two levels behind (the Vayne on average will half about half of her required xp to level up). Also because you're ahead in level you have prolonged death timers; this means that Vayne gets to push in a wave that gains her experience and denies you experience. Once all is said and done you and Vayne are back to even, which is good for the Vayne player who has played far worse than you all game. Riot loves punishing good players by removing the influence of skill from the game; thanks Riot!

Shutdown xp: https://leagueoflegends.fandom.com/wiki/Experience_(champion) Death timers: https://leagueoflegends.fandom.com/wiki/Death