Overwatch does this as well. When you start your session it matches you up against inferior teams but the more you win, the harder it gets because it puts you up against better teams until you lose. So for example me and my team won 6 straight today which has to be the most we won in one sitting, if we had kept running I’m certain we would have hit a hard MMR wall. Usually we win 2 or 3 and then get shitted on

Weirdly with a 5 stack there’s less variance though because with less than that it will literally give you worse randoms to balance the teams if you and your party have been playing well and the reverse if you’ve been losing. Plus the best two or three players can consciously communicate and pick up slack from the weaker players/mitigate weaknesses (vs having the skill and hero pick of the randoms fluctuate/change)

It’s honestly scary how well designed it is to keep you chasing those dopamine highs after the inevitable lulls