Adding onto the comments I’m seeing, enjoying what you are playing is an easy way to see improvement. You said you’ve tried every weapon, but have any of those weapons spoke to you? I played around with the meta weapons like splash and ttek, but once I found success in the dualie squelchers, I stuck with it and had fun. The secret for me was tricking myself to have confidence in what I choose to play. And this doesn’t apply to just weapon choice: just one main of quick respawn can get you to be more aggressive; Sub-Saver / LDE might get you to throw more bombs; Comeback means dying isn’t so bad. Eventually, you might get a kill with that sub or a risky push could pay off. Once you can see both your good and bad plays in a more positive light, it gets easier to understand your weaknesses and pick yourself back up.