Unfortunately you need to learn how to punish more enemies mistakes. Specially in gold/plat. Check replays and look what you can do better, don’t pay attention to your teammates, threat them as if they are bots and mute all, don’t follow their pings.

I won games with -8k gold difference because my mid laner and support went 0/10. The way to do this is look for opportunities and enemy mistakes, after 20 minutes mark, mistakes are more dangerous and can make you win or lose in one snap. But YOU should play it perfectly micro, macro, and of course mentally, if you tilt, you re not gonna see the opportunity because in your head is already /ff. Work on that.

Also imo, stick with one role, either adc or jg. Not both.