Ranked seems to be at a standstill for me, I need help urgently!

I think I've legitimately hit the place in the ranked ladder where no matter what you do as a single player, if more people on your team do badly than on their team, you will lose without a question. Ofc if you are 10-0 there's a chance you'll carry but mid to high Plat players will not usually keep running at you giving you kills over and over. Some might, but for most games that will not be the case, and you'll only have a minor lead. On the other hand, my botlane will often feed hard, even in a 2v2 scenario. I look at 25 minutes our support is 0-9. This happened two games in a row. Don't take this as a oh my team is so bad complain thread, it isn't quite that. If you look at my ranked stats for the last few games I admit I did not do well in a few of them, but overall, I perform solid. I only rarely am able to say, "I was the reason my team lost" or, "my decision there cost us the game." It happens, but is not the case.

I learn from my mistakes like that time I went essence reaver on lucian. It's not the best. But the more I play the more I feel helpless, as just a cog in this machine where if another cog is rusty will fall apart and fail. Playing ranked solo queue is just a demeaning experience that makes me feel powerless.

I have considered playing ADC as it has the most - lategame power, early dragon control, and if fed, will have 2-3 fed players, rather than if just mid or top wins - 1 fed player, as the jg will most likely be focused bot. However, I don't have a support main to duo with, and the supports I get in solo queue can be hit or miss awesome or just 0-4 by 10 minutes.

I just don't understand - sometimes the more a person kills my teammate the more inclined they seem to try fighting them again.

I'm sure if I had a consistently good support I could carry out of Plat, but I dunno if thats the case. My main to carry out of silver was Garen top, but he is not a viable carry anymore in Gold. In Gold, I carried with Viktor mid, but midlane just cant carry in Plat unless extremely fed, so I am just thinking of ADC. Just nobody in solo usually wants to support or has it as their main, so I'm stuck with some bitter bozo who feeds their ass off 80% of the time.

Almost everyone in Diamond is an adc main, or at least the majority is, and that says a lot. I've heard that even Challenger players have trouble solo-carrying out of Gold. GOLD LEAGUE. That's something.

I know the whole "You've reached your skill cap yada yada" shpiel but I kind of have to disagree. I play in tournaments with my premade team and we have more than once faced diamond opposition and gone even/won before. If I can lane against Diamond 3-5s in the mid lane, I should be able to get out of Plat. Isn't that the idea?

Either way. Please offer your opinions on this and any advice you may have. I would greatly appreciate it