First, let me define what "elo hell" is. Elo hell is a point in your ranked climb where you feel like you're "stuck" at that elo. Your recent games are either very even or negative in terms of win-loss ratio. You may experience consistent LP losses or staying at the same LP. I will provide answer to this definition of "ELO HELL".
You have to improve at the game. Find out the trends in every game that cause you to lose. What role are you playing and what is your job on that role? What can your champion do? What individual mistakes are you making that lead up to you losing? Are there things you aren't doing this game that could have a big impact on the game like warding more often, paying attention to the minimap, or csing better? Ask yourself these questions and find the answers. This will help you improve and become better at the game. Become a big threat and huge factor in each of your games. This will give you more control over the fate of each game.
Also, you're wrong about jungle. Jungling is arguably the best role right now to carry with. There are so many strong picks in the jungle and well-timed ganks/counterganks as well as rotations towards objectives will swing the game to your favor. I would say for support, it depends on the champion, build, summoner spells, and the decisions you make during the game which will allow you to carry. Supports do NOT provide dmg late game. Remember that.
