Need Advice On Champs

Hey everyone my name is Lettesanity!

I'm S4 and have been playing for a year or so and I'm having some trouble with choosing and finding champions. I always get a wrong impression of a champion before I play them and when I do the champ turns out to be completely different than my imagination. For this reason I've never been able to find a stable champ to be able to carry my games.

Well a little bit about me, in a 1v1 my mechanics can outskill at least a gold player, what I have trouble with is decision-making. I always path wrong or pick the wrong fight and oftenly end up behind because of that. I'm bad at assessing my situation basically.

I need a champ that does tons of damage, relatively safe, lane dominant, can outplay, get out of situations cleanly and have a big impact on the game in general. Someone like azir would fit, I'm mainly looking for mid and top laners. These are some champions I play a lot rn:

Also what is the best position to play in silver to win games? I've experimented a lot but can't find an answer :\

Thank you for your help!

~Lette