I don't know that much of matchmaking, as this always becomes something big for every game and is constantly discussed, so I typically ignore stuff related to it, so please do correct me if I get anything wrong.
But doesn't there need to be some form of MMR,SBMM and whatever?
You can't really matchmake players into a lobby without having any idea of how good they are, otherwise there would be a major imbalance in the lobbies.
There are many different ways to calculate these numbers and matchmake based on them, each having their own application depending on the playerbase, game and playlist.
Without such a system, it would be impossible to make lobbies that feel good for anyone, it's a requirement if you actually want to matchmake a proper lobby, regardless if it's ranked or not. You can't exactly put a Bronze with a Pred and expect the Bronze player to enjoy the game, that's not fair at all.
These numbers are typically based on your statistics and recent activity, and as these numbers are separate from ranked, it would mean that your activity within pubs itself has resulted in you getting matched in such a way.
And to get it right, at least from your main post.
You want to get matched into a lower skill level so you can destroy those lobbies, or what is it exactly?
As you are mentioning that you don't want to get put with your own skill level and clearly don't want harder lobbies, it would mean you want easier lobbies.
And I get it, it's fun to destroy players, but it's not exactly fun for those players to be matched by someone that's above their own skill level.
Now after reading your reply to recon, I see that the issue is a bit different than you're explaining.
You are being matched with players above your skill level, not within yours, so you rather want players around Diamond-Master rather than those Preds?
And well, as for your friends, the matchmaker usually uses the highest rank from the squad, if that were to be you, then yes, it would put you in those high-ranked lobbies to not make those low-ranked lobbies one-sided. It's a bit selfish to expect them to make easy lobbies for you, whilst absolutely ruining the game for those lower-skilled players.
It is of course an issue when you want to play with your friends, but you have been playing so well that the system has recognised it, so it wouldn't really be fair to put you in a lower skilled lobby just because you are playing with your friends.
Also keep in mind that KDR means very little as a sole statistic when it comes to their performance in-game, so this is probably not the only thing used when calculating someone's hidden rank.
And yes, it would be recommended to play on a new account if you want to play with your friends in those lobbies, but if you need to keep making new accounts over and over then it does indicate that you are stomping those lobbies, so it's only logical for the system to move you up.
So you are technically proving that the system is working as it should be, since if the system wouldn't exist or if it weren't working, lobbies would have much more variety regarding skill level and whatnot.