Changes in an individual players Matchmaking Rating (MMR) are determined by which team won the match. When you win, the MMR of all players in your team goes up, while the opposite is true for when you lose.
Can you get banned for leaving games in Valorant?
You may receive a temporary ban for leaving mid-match, but the penalties are not as harsh as dropping from a game without officially leaving it.
What happens if you leave a Valorant competitive game?
So right now, if you leave a Valorant game or match, you will not be able to queue up for another match until the game you left finishes. What you can do though is reconnect to the match you just left. For some games, quitting leads to a reduction in your matchmaking rank or competitive rank.
Does Quickplay affect MMR hunt?
The matchmaking changes in the new update will have no impact on the Quickplay experience. Due to the population size of Quickplay, adding brackets or an extensive matchmaking system would only result in a lot of empty matches.