Plat 3 player, played all my placements in plat-diamond lobbies, go 2-3 match MVP'ing both wins (one with 30 kills), placed silver 2. Silver 2? Like, what even?

Is it me or is this game unplayable for casuals in it's current state? I am not even bad at the game but even spike rush and unrated feel like a sweat fest of people that aim train for 12 hours a day and stuff.