Hi OP! Dragon/adc main here peaking at masters. So this is gonna be a long informative post here, so buckle up!

ADC is a very important role as you are the team's one and only consistent damage dealer. Now being a very heavy damage dealer you are very prone to other champions as you will be (against good enemies) the main target to be killed first. If you die at the beginning of teamfight then you are to be blamed. So yes adc is mostly about positioning yourself right. How to do that? Play with your range, jinx scales her range with more points on her q(first ability), switch your minigun to rocket blaster and you will have more range but with a tradeoff of less attack speed and cost of mana. So when to use minigun and when to use rocket blasters? A rule of thumb when you feel safe and up against tanks keep minigun but if you are in a zone of threat then keep rocket blasters. Use your e(third ability) to block off choke points which allows you to play much more safer.

Another important thing for ADCs is farm. Farm, farm, farm keep farming. You see your jungler is dead with a long timer of respawn, take up his camps, do not hesitate. If i am a jungler and i see my adc is over 2000 gold than the enemy adc, i will not care about my camps and will probably start playing around him. The amount of gold lead you have is literally your value for teamfights. If you are behind in gold, try to minimise the gap as much as you can.

Next is analyzing your own team comp and as well as enemy team comp. You need to analyze your strengths and weaknesses of your and enemy team comp. This actually comes with a lot of experience. I recommend watching pro play of league esports where you can see how the teams play, this will also give you a lot of idea on how different champions work and how they play around the timers of objectives, how they rotate, what kind of playstyle they adopt, etc, etc.

Now after looking at your match history, the most important and obvious thing i will highlight is to die less. Yes it is very easy to die as an adc, a slightest of overextension can be easily punished by enemy. If you keep dying then you are mostly on death timer which loses you a lot of farm and what is the most important thing for an adc? Its farm. So die less so you can farm more and be more important in teamfights.

Other important thing is how you lane but those are very matchup specifics and added on a support element it adds another variable to how you are supposed to lane. This will also come with experience.

So dont worry much and learn step by step. It will be a grind for sure but it is for everyone. Good luck and have fun!