Trash ass rank system

This rank system for "supports" is so broken. Supports can actually carry games! I'm a plat 3 bard main yet I'm matched with lower ranks, meanwhile, my opponents are a higher rank. Like how is the support the highest rank on the team how "balance" is this rank system? There's only so much I can do like I had a gangplank troll building ap going 3-7 top lane a kindred 2--9-mid liss 7-7 and adc ez 5-10 yet here I am with 7-8 most kills, as well as being focused because the enemy team knows I am "carrying." I can find picks, I have map awareness, I'm doing callouts, I'm roaming as well more than the jungler, whatever I can yet none of my comrades got any of that. When will this rank system be fix? I've been waiting patiently since s6 supports got a voice too.