Disable autofill in ranked, period.
It's supposed to be a test of your knowledge and skill, not your luck. It's all well and good to have autofill in norms. People who are playing casually probably want to find a match faster, and aren't hindering anyone's climb when they troll after being autofilled-- which happens more often than not. But if someone wants to play Ranked, it's unfair to force them into Support when they want to play seriously.
The mentality that everyone should be able to fill works for professional players. But for the rest of us the only tried and true method to climb is to pick a role and one or two champions to know inside and out. They can't just tell us that if we didn't pick support, we had better learn it.
. even lane support
carries really hard