SBMM completely broken

I'm not gonna argue in favor of the matchmaker. It really is pretty bad. But in your case, here's the thing: 1.5 k/d. That's why you're ending up where you are. I'm not saying that when the matchmaker whittles it down to 0.6 then you'll be back in your properly balanced lobbies. You won't. But still, 1.5 is a thing that I'm not sure you can have and still say "not a major sweat." If it came easy to you in the past then that's great, but now you're seeing the other side of the coin, the game that most of us have been playing since... forever. If I have any advice, it's to stop making an effort in these kinds of lobbies. If the matchmaker sees you trying against 4k/20 players, then it really doesn't care that you always lose. It cares that you're still willing to try. And it will continue to make you try. Until you stop trying. With most players that takes the form of quitting the game. With me it took the form of a lot of quitting of matches. Your experience will get better either way if you have the stomach for it.