Honestly, this is just venting, but:
I'm currently sitting at a 48W-49L record in ranked in the new season. I have been in my promos to Plat4 ten times. TEN. And have lost every single one.
This means 60% of my losses in this whole season are in promos. It means that outside of promos, I have something like a 65-70% win ratio (most of them were 1W-3L promos, meaning my win/loss outside of promos is something like 36W-19L.)
And yet I can't bloody climb through... sheer dumb luck in that particular set of 5 games? Promos suck. They suck hard.
Does matchmaking work differently when you're in promos or something? This honestly seems too ridiculous to be bad luck.