Really you have to straight-up break the game at this point.

There are some things about certain builds that make the game unfair - seriously unfair - for your team, and that's pretty much how you need to play League now in order to win.

Screw winning or losing lane - just pick things that are blatantly OP and break the match as a whole and you'll probably win the game. From experience, way too much experience, look for what makes the game completely unfair and do that thing in order to win. Nothing about League is fair anymore. That's Riot's ultimate vision, unfortunately.

Take jungle AD casters, for example: take Resolve as either primary or secondary with Revitalize and Conditioning. Get both buffs quickly (i.e. blue -> camp -> red) , then rush Tiamat -> BC -> Sterak's. If the enemy team has multiple tanks you can rush BORK -> Mortal instead. Never upgrade your machete and just run around inhaling creep waves and blowing people up while scaling into lategame. This completely breaks the game as Tiamat or BORK annihilates everything, be they champions or jungle creeps, and the resistances + bonus sustain from Resolve runes makes you tanky without having to buy much/any resistances beyond Tabi.

So next time you're in a game and raging at how useless your team is, realize that you didn't break the game for your team either. That is the only way to win anymore and you should find that 'fantasy' for your champion and abuse it before queue'ing up again. That's the only way to play League now.