How does one win a promo series?

Look at my match history, every defeat was from my promo's and pretty much every victory was to get there. It doesn't matter if I'm fed I will lose anyway. Am I cursed or something? It's not even that I play bad during the series but guess what, 4 of my teammates magically go 0-6 and are completely useless throughout the entire game. And after losing said games, suddenly my teammates become better players who actually know how to not fall behind 3 levels before the 10 minute mark. During every loading screen, I don't think about my own lane matchup or things I could do better. I think about how far behind my botlane or toplane will be in order for them to troll or go afk.

This game is getting boring really fast knowing that I have no impact on my games whatsoever, since matchmaking already decides if I lose or win.