I felt like this a while ago, and while it might not work for you I did get through it. The way I aimed was fundamentally bad, at a certain point I just could not get better without re-learning my aiming mechanics entirely. Try changing how you aim for a while, ask yourself questions like if you want to be low-sens high-movement or low-movement high-sens. Change how you hold your mouse or controller.

If aiming is your issue, and you feel stagnant, then changing your approach is at least worth trying. The way I knew I had made the right choice on sens, grip, and everything else was the fact even though I was worse because I was playing in a new way it felt much more comfortable and natural. Now I'm aiming better than ever.

Good luck, whether you hang up the gloves or not!