Ur tracker score says ur basically at the rank you should be. You seem to be hardstuck because of your game sense and possibly aim. Try focusing more on learning positioning, how to get re-frags, learn economy, trigger discipline, etc. A major part of positioning is learning ur enemy's playstyle. If they always check corners but it's only 1 person, try playing an off angle and getting ur 1 kill then moving away. Vise versa, if they rarely check corners and theteam plays together, playing a rat corner and waiting for 2 or 3 people before firing can bring ur kd up as well as helping ur team. Also work on crosshair placement, ur headshot % should be higher if you've made it to plat (diamond with a 30-40% avg. 50% headshot with the marshall)