You have a very overloaded question that is not going to bring you the answers you need to hear. Hopefully i can convince you more than some of the others who will just tell you "pick x champ they are really strong"
You might hate hearing this, but the best thing you can do is just "pick" the champ you enjoy most. Because whether the champion statistically has a 49% winrate or a 56% winrate, if you arn't having fun, and you dont enjoy a specific champion.. you will not climb/win. Find a champion you really enjoy, and learn the ins and outs of it.. Don't get too caught up in a few winrates on champion.gg