CSing is pretty low in those ranked games.
Based off op.gg and the elo, I would say Renekton isn't being fully utilized via combos or playstyle in early game.
There's a term in games called "Stop the bleeding" which is to change your playstyle by playing significantly safer to stop dying. It's not meant to play for a good kda while risking the game, but it is meant to stop any possible enemy snowballs. There's a lot of deaths in games both won and lost.
I would also assume your wave control is little to none based of the deaths. You can use wave control to "Freeze", "Crash", or zone enemies from the Minion wave. It's essential to use in playing both safely and aggressively.
Warding is a standard but you have some control wards in the games. That's great.
To fix csing, go into custom games with the champion you plan to play in ranked a lot and just cs (Prefferably with the starting items or no items at all). Once comfortable with med/high cs scores, go into the custom game with a bot or two in the lane to practice csing under pressure. Note : Throughout all this, you should not be using abilities. This also hones on your positioning and matching the enemy.
Wave Control can be fixed through a few youtube videos.
If you want a copy and paste route then TopSoloRenekton or RenektonTopOnly has Renekton based content but it's mainly a stomp so I kinda dislike those.
If possible, find videos called "Playing from behind" for LoL, not many players know how to do it because most videos people watch are just wins, stomps, and general neat mechanics with the champion rather than understanding how to play the game.
Note : As you climb, games will become more difficult is already a given. What's not a given is also the amount of meta slaving and repetition of optimized builds and meta champs that will be in your games (One of the reasons why people like to smurf is to get out of these conditions).
Edit1 : When I smurf, I tend to have more confidence and fun playing different types of champs with different builds (You will have to raise the smurf from lvl 1 to lvl 30 though and that's tedious). At this time, both my smurf and my main are at the same rank for different reasons entirely where I play what's somewhat good on my main and play what's fun on smurf [God I love Xerath Support]. Yes, playing a champion and having "fun" can help but it's hard to do that on a main account where you also worry about your rank while on a smurf, you don't worry about climbing but moreso just playing the game.
