After a quick look at your OP.gg, 2 things you can quickly do to improve:
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In almost all of the games you lose but play well in, the enemy ADC is carrying hard with few deaths, and the game is dragging on. You need to take them out more consistently. Don't waste your abilities to get the final blows on other enemies, the enemy carries should be your #1 goal every teamfight. Killing them more allows your own carry to scale up, and be more useful even if they are a bad player compared to their enemy
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You need to improve your farming and plays for objectives. In lower elos assassin players often make the mistake of roaming TOO much just to fight. Going 10-0 looks great but means little if your opposing laner has a heavy farm lead and is pushing your tower, especially if your roams are only leading to kills and not objectives because most carries will outscale you.
Other random tips for an easier climb out of bronze from personal experience:
-for top: play a scaling carry that is good at split pushing, allows you to 1v1 easily and even 2v1 with a lead
-play an ADC bot that can bully lane. allows you to win lane most games and snowball.
-play a champ with good CC. Everyone in low elo likes to play carries with very little utility, build all damage, and fights are just everyone diving and combo mashing. Games often come down to who has more stuns, especially as the game time lengthens (which happens often in low elo).
-more damage items do not always mean more damage. If you are already killing everyone easily with 2 damage items, you don't need a 3rd right away. Buy some utility or defensive stats which will keep you carrying as the enemy's kill potential grows while they slowly scale