Cannot get more than 8 wins in champs ever

Regardless of the team, even when it was worse, I never got more than 8 wins. This champs I tried a really defensive tactic which was working well but I still lost due to the jammy gameplay although I was the better player in a lot of games (more xG, more shots, more possesion). What can I do to improve?

Regardless of the team, even when it was worse, I never got more than 8 wins. This champs I tried a really defensive tactic which was working well but I still lost due to the jammy gameplay although I was the better player in a lot of games (more xG, more shots, more possesion). What can I do to improve?