Is there something I'm missing or am I just trash ?

I've played this game for 30 hours, I am level 35 and I don't understand. I feel like i'm just getting worse and worse every game... It's not my first FPS, I played CS:GO for more than 300 hours a while ago.
I tried everything : single firing mode, full auto, burst, pushing, camping, aiming, hip firing, aiming for the head, for the body, even using NVIDIA GeForce Experience to make the image clearer, nothing works.
I am just getting destroyed by people I can't see, and even when I am first on the leaderboard, I am not enjoying my time on this game.

So I am wondering : is there a meta I don't know about ?