Need help on what champ to main (Serious Post)

So i was finally able to reach gold. But during my "climb" i realised that most of the champs i use are too simple and one dimensional. I feel like to climb even further and get better at the game i need to: 1- Make sure i improve my basics even more (cs'ing properly, trading properly, wave management and shiz like that) and 2- tighten my champ pool to champs with a large learing curve (champs that take long to master). I currently main Wukong mid and enjoy playing champions like Jax, Quinn, Fizz, Trundle, Diana and Viiktor. Apart from Viktor and Wukong i feel like the rest are just way too simple. With wukong i feel like you have some sort of versiatilty as you can go full lethality and become an assasin or go bruiser/tank to soak up as much damage while you can still deal good amount of damage. i have tried yasuo and as much as i love the champ and want to one trick him and master him i feel like i am not good enough at the moment to main or play him in ranked (even though i do sometimes anyways lol). Anyways the main purpose of this post is to get a list of champs that take time to learn but are worth the struggle. Mainly top laners and mid laners wpuld be great. P.s : English is not my main language so if there are parts that are not clear or if you need any more information just ask me. P.p.s : I really want to get good at the game so if you have any tips that are not necessarily involved with champs please still leave them here. Ty for your time