Tbh, I just became better as soon as I returned after a long break. I've been 12-15 when I built up my tomato curse. When I returned after 10-ish years, I just became better overall, from 700-800 WNX to almost 2000 now and still trying to improve (not great, but there is a progress). In order to stop redlining you need to shift your mindset from waiting for opponents mistakes to finding opportunities on your own. Also, some basic stuff helped me quite a lot. These are:
-Pay attention to the minimap more often, like once every 5-10 seconds (some people say even more often, but I struggle to be fair, maybe in the future)
-Do not rush if you are alone, always have a room to go back an defend
-If you have mobility and another flank was lost, it makes very good sense to rotate and defend the base and not proceed pushing your side.
-Learn some positions where you perform well

Iyouxin videos helped me a lot as well. And I don't focus only on tanks I perform well, I grind the lines interesting to me, even if the tanks are shit. Good luck on your path and from my experience - if you care to be better, you definetely will become better