League of legends question

Hey guys.

I want to ask you some questions about the game.

I used to play it but i stopped playing.

And now i am back to it,i want to ask you some questions.

I want to ask you what would you recommend to play,champion or lane.

I would like to be an one trick pony,get really good at 1 champion because i probably will never go pro.So i want just to get good at 1 champion and be a high rank player :P

Also i am not really that good so one trick pony is actually a good thing for me.

OK my question is: who should I one trick pony with?

Or what lane should i main?

I really like heimerdinger as i played him in free week,i am ungankable with him and i carry games with ease.Also i do somewhat well in the early game with him and early game is my weak point with every champion that i play.

But i dont have enough ip and its often considered a noob champion so idk lul.

So i decided to one trick pony tryndamere because he is agressive,good at split pushing,can do fairly well in teamfights and can backdoor easily if needed,he can splitpush but i am not really that good with him.

I like champions with some cc,that can jsut turn teamfights around,i like them having a bit of life and some damage.

I used to play mid just to carry games but i dont really feel allright playing it because its not me.Like stay back passive and farm,have no life,burst focused and gets ganked a lot.Heimerdinger is not that case he can just outplay.

And in toplane i can go agressive and win,i can farm without staying back,i have some life and i actually can outplay easier.But idk really xD

And i am somewhat agressive but i always do worse than playing passively in game xD

What lane or champion would you recommend me to play?I want something that i can carry with so no support because i dont really like it aswell because i cant go for kills as i like and i am not a supportive guy,that heals a lto and stuff

Also how can i stop focusing on learning the theory of the game,reading a lot about and just focus on playing and getting better?

And for the last question,what can i do to stop raging and tiltin and start saying shit? If something goes bad for my team i just tilt and start typing shit in chat.I know its bad and that makes me toxic but i really want to stop that and just focus on getting better and stuff