cheat and don't get caught
this sounds very familiar to what happened to me
I got Global on 50fps after 3k hours, played some matches before on Faceit on 30 fps, then I had to start on lvl3-4. I got lvl8 instantly, staggered there for some time, took a 6 month break, came back, got to lvl10, 2.5k elo and eventually 3k+.
All of this was 90% of the time SoloQ. How did I do it? Well you just gotta carry as hard as you can while also controlling your team to a point where no one trolls etc. Try not to tilt, keep calm and always be positive. Also never give up.
tl;dr just have the right mentality and practice your mechanical skill, you will eventually win more than you will lose (if you lose more than you win after a longer time, you're probably doing something wrong)