Looking at your match history it's very easy to see why you're Bronze 4 or 5 consistently.
- You have too many deaths per game.
I see one of your more recent games you played as Vayne and died 18 times in 35 minutes. That's insanity and borders on intentionally feeding. If you die more than 10 times per game you're doing things very wrong and obviously out of position far too often. Realistically, you should be dying 0-6 times in 35 minutes and absolutely no more than that.
In many of your games you barely scratch the 150 cs mark. Recent games - Vayne (35 minutes) 118 cs, Jinx (22 minutes) 125 cs, Miss Fortune (40 mins) 193 cs---although that game you did have 15 kills unfortunately also had 14 deaths, Lucian (31 mins) 81 CS. Oh my Goodness. You can't possibly ever hope to climb if you're not getting good cs values. To get out of Bronze I would suggest getting at least 130-150 cs by 20 minutes at minimum.
- You practically never ward.
I see that you are one of the only people on either team that buys control wards, that's good! On the other hand you basically never use your other wards at all. I see multiple games where you place less than 10 wards in a 30-40+ minute game, that's just not going to get the job done. How are you going to have vision of the enemy team if you're not warding? I just don't understand the mindset of low Elo players.
Here's one game where you warded TWO TIMES in 31 minutes. Holy shit. How is that even possible?
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But here's one interesting quirk. It seems that every once in a great while you are capable of having a crazy good game. I found a Xayah game in your match history where you went 21/5 in 30 minutes with almost 300 farm! You didn't ward that much, but everything else was amazing. How the Hell do you play that well---with amazing CS one time and then not do the same other games? I understand everyone has bad games now and then, but it looks like you're capable of playing well so I don't get it.
Ward, cs, better item builds, and good positioning (leading to fewer deaths) will help you greatly along the way.
I didn't look at your runes and masteries so I can't speak to whether or not those are in good shape, but just follow what I said and you should climb out of Bronze. Unfortunately, since you have played roughly 875 games in Bronze your LP gains will be fairly meager, but it is absolutely possible to climb out of Bronze even with that constraint.