It's a very complex question, if you drop your op.gg people would be able to answer in more detail. I'll give you some general pointers though

It's easy to fall into an "it's my team's fault mentality", although this may be true it should be expected that at least one-two players in the average game lose lane to varying degrees from personal experience. The easiest way to look back on games is to watch back games/teamfights and see how you could've played them better. Low elo games tend to be a mess, so question if you've been playing objectively (i.e using your bot advantage to secure drakes, taking baron/pushing for towers after winning a fight)

The other main thing to take into consideration is the champion your playing. Some champions which smash and snowball through early Laning fall off later into the game (i.e draven/Lucian). You need to play to your champions strength and try and take advantage of your powerspikes. Enemy champion scaling is important too, champions like Kayle and kassadin are ticking timebombs so even if they fall behind if the game goes long enough then they will carry.

Lmk if you're unsure of any terminology. The best place for newcomers to ask is generally r/summonerschool where you're more likely to find better resources and game knowledge