Is Riot purposely making promotion hard??????

So I just failed my promotion to d3, again. But this time, I found something really disturbing. As you can see the link that I posted, there was a Kha Zix game, and losing that game failed my promotion. I went 4/7/5. "Welp you were trash and didn't deserve to win anyway don't blame Riot or teammates for that loss", you might say. But I'm not here to complain about how I have a Veigar bot and went 1/8, I'm complaining about the Ahri that somehow got placed in my team magically. As a jungler, I check every one of my teammates during the loading screen to find out which laner has high winrate or is skillful with the champ and will try to snowball that lane. However, when I checked our Ahri, she was only level 38. I thought she was smurfing or something, but when I checked her profile, she only played 3 ranked solo/duo games and lost all of them, and it wasn't like she has high mmr from last season or something. OP.GG says she was only plat 5 in season 6 and there are no ranked records of this player during season 7 or 8. Yes, I do understand I'm a hardstuck d4 with negative winrate, but hey, I'M STILL DIAMOND 4. All the other players have close tiers to me, the lowest one except Ahri was in plat 1 promotion to d4. So it ended up that this player played pretty awfully, missing most of the easy taunts and outskilled by the enemy Ryze. I'm seriously wondering how does Riot's matchmaking system work now, like why would I get a s6 plat 5 mid laner for my promotion? Is Riot really purposely making promotion hard by giving you shittier teammates than those you normally get?