Need advice to climb

I started playing LoL in that in-between (S4-S5) seasons stage. I was really bad to say the least. I have always played mostly Wukong (about 90% of my matches). Fresh into LV 30 I hit rock bottom Bronze. I struggled to get to Silver and learned many things on the way. Right before S5 ended I made it to G5. However, I took a few months break after that, and when I rejoined in S6 I kept finding myself tilting. And I feel this is partially the reason why i haven't been able to get out of Silver this season. I feel like I should be Gold.

My thoughts on why i might tilt? I let the fact that sometimes you get a feeder, or troll that makes it nearly impossible to win a match get to me sometimes. I try not to, but when it happens every 2-4 matches, you begin to wonder how is it that it can happen so often. Also, whenever i try a champion other than Wukong in Ranked it never goes well. The times i do really well with those champions my team is bad and the times i do bad with them my team cannot carry me. So it is hard for me to want to try any new champions anymore. I feel safer with Wukong. Lastly, and the reason why i believe i should be in Gold is I do well with Wukong in most of my matches (even the ones i lose). Even in the matches that my team feeds i make it out with about 6 CS/m, 3+ KDA and i keep any salt to a minimum. I don't give up on matches for a second, i keep my head up and my builds revolve around team support, like a BC, RO or a Zz'Rot Portal.

There must be something i am missing, something i do not know. I have really good mechanics with Wukong whom is LV7 mastered and 450k+ mastery points. I have good knowledge of the game such as champions and their abilities, objectives win games, farm is very important (i aim for 7 CS/m), items, wombos, vision is very important etc..

What is something that helped you climb despite you feeling like you had all the things you needed already?