Attention players in all ELO
If you ever complain about "winning lane, losing game" you need to take stock of what you're doing in game. Just because you run Darius top lane and dump on a Jax, if you spend the rest of the game just continuing to 1v1 that Jax and not taking objectives or roaming or helping your team then that lead is worthless. A lead in lane is useless unless you can find a way to transfer that lead to the rest of your team. Get teleport flanks, be a split pushing threat, or be a monster in teamfights. Just because you won a 1v1 matchup in laning phase does in no way mean you deserve to win that game. Transfer that lead to the rest of your team and then you can win.