The main problem for me is not that I get bored, the problem is that I like playing too many champs. I can't stick to one champ, because I can never play more than 2 games with the same champion. The role is also problem. I can play any role decently.
just choose a lane(s) to main and get good at that lane, you don't need to main a champion. Just get good at the mechanics
Play Ezreal and you will have found your man.
So what's the problem?
A Yandere isn't focused on a single target?
God help us all.
Step 1. Play Mid as it is arguably the most fun role. Step 2. Decide what your play style is, but guessing from your problem, you don't have a specific play style. Step 3. In that case, get a champ that has a badass backstory. Step 4. Get that champ to level 5, then move on with your life.
Getting a champ to level 5, especially the high skill cap champs, will take some time. I think that in that amount of time, anyone can get at least decent at a champion, even if it is 
