Matchmaking Team Balance issues

Ok, so far I’ve mainly played FFA, BTB, and Warzone modes. Platinum in FFA (is that a “bad” rank btw?), and tried diving into games of normal Slayer. Both matches so far I’ve seen 4v2 and 2v4 matches. What is the issue? And do these matches of complete imbalance affect your overall ranking, even if you topped the scoreboard on your team?