Marked accounts? Cursed mmr? What even is this?

Hey guys, I have an interesting claim here.

So, recently I had started an alt (smurf) to play with my lower elo friend. This account im posting with is Gold IV and has the mmr of such. Its stayed this way for a long time. This is not the smurf. My smurf is Kurieko.

Now most of my games usually end very sloppily, one or two people on a team legit int. Sometimes up to 3 or 4. For the vast majority of games.

I can pull up my match history and show almost every single game has someone who basically inted the whole game. Doesnt farm, doesnt show up to teamfights, whatever. SOMEONE was high.

Now Im not going to make this a post about this being "This is why I lose all my games" etc. Here's where the smurf comes in.

My smurf is basically the exact same rank and mmr now. Except, that account does not have this experience AT ALL. Everyone is equally bad or good and the games are WAY more consistent than this account.

This isn't a coincidence. On account in Gold IV MMR facing with and against int-ers almost every single game, and another account RARELY seeing them.

My smurf climbs steadily because I consistently do well. This account bounces back and fourth between gold IV and III due to inconsistent opponents and teammates.

Comparing the two match histories, its clear that one has games with rare inting teammates, while another has them common.

What does this mean? Are accounts flagged for gameplay? Im sure this isnt a fallacy, this large of a sample size should be enough to prove its not a coincidence....