Not seeing any skill improvement over time invested?

I'm level 52 and im sitting at 770 hours, mostly in the ussr and im horrific at the game with an average winrate of 48% percent and kd of around .8. I've hit 11.7 and i just keep getting worse, the only vehicles im even close to capable in are the late IS-2 and T-10m even though just barely. The highest br vehicle that ive used is the T-80u with a kd of around .47 and its not even close to being spaded at 105 games. Ive tried every piece of advice I can think of and nothings helped.