what do i do in this ingame situation? what should i do? i really need help with this please

i very frequently get into games with someone who doesn't want to play the game unless they are the ones who carry it. what do i do in these games? if they get ahead, its very easy to play around them. hell, if i'm a midlaner but my top lane riven is 20/0/0 ill even build support items to help them carry. thats easy.

i don't know what to do however, when i have a lane that doesn't understand if they literally afkd we would win, but instead insists on trying to be the carry. this happens frequently enough that i feel the need to ask for advice.

here is a recent example (but again this is a **repeated **issue not a single occurrence) example of actual ingame conversation at plat 3/4 ELO: _score is about 8-4 in our favor

me (autofilled to support)-" corki just stay under tower and be passive, every other lane is winning we can carry you" corki (who is 0/4/0)-"but if i stay under tower i won't get cs and exp and i'll get further behind" jungler-"but it's better to miss cs and experience then to die and then miss cs and experience" (which is what i try and communicate) corki-"well maybe if i had a botlane i wouldn't be behind" meanwhile bot lane is 4/1/4 and up 30 cs....... me-"its ok if you get behind, we just can't have the enemy kat ahead. every other lane is winning we can carry you" top-"ya just be passive and pick up what you can under tower"

corki continues to die solo, tries to make impossible plays with his package, towerdive two turrets deep, etc. corki repeatedly walks right next to kat daggers to try and cs, all 4 of us ping danger on top of kats daggers on the ground. corki doesn't give a shit, proceeds to spams chat with "asdfadsfa" to the point where i'm surprised chat didn't make him wait before posting more messages. corki ends 2/11/0. his enemy kat ends 18/0 he spam pings the entire game, and just goes "lol" repeatedly. doesn't listen to any bit of logic, just attacks his teammates who are doing very well in the game. states he doesn't care that we lose. tells our teammates to kill themselves even though we are trying to be supportive and are undeniably winning both laning and macro game. but he isn't 20/0/0, so we have to lose.

what do i do? how do i stop these people from self imploding? there are always going to be crappy 12 year olds riot doesn't ban because they want the higher playerbase, i 100% get that, but so what should/can I be doing to mitigate their impact? do i just not tell them to play safe? i genuinely don't know what to do... happens easily 3 out of every 10 games, am i starting it by asking them to play a little safer?