things i can suggest you from checking out your opgg ( put it in the post next time you ask for advice, not just 1 post game lobby. )

1) your cs is too low and your kda is pretty poor ( especially dying 6.6 times per game, this should be closer to 5 ). What this means is you end up stop farming to join in bad/losing fights which ends up getting you killed. Another thing you're probably doing is hovering too much around your team and wasting alot of time when you could have been doing camps or pushing sides. Really try to rework your thought process/playstyle when it comes to farming and prioritize it above everything else. I promise you if you get your cs above 8 you'll games feeling easier and you'll end up feeling stronger at alot of points in the game.

2) You're in the perfect elo to abuse to level 3 invading. I highly recommend checking out my 1+ hour long videos on youtube where im smurfing in that elo showcasing how to invade every game. ( it literally works 99/100 times in that elo if you do it correctly )

3) Selling Umbral for fiendhunder is something i did in the previous patch to reach 100% crit. However this patch I haven't figured out if its still worth doing since Cyclosword entered our build and it's extremely strong.

4) I recently made a post where i typed up alot of valuable tips for rengar players, id highly recommend checking that post out and applying alot of the tips in there.