Mhh my tip is close to what you said. So I was hardstuck diamond 4 every season. I feel like the skillgap is huge.

If one teammate died before a fight actually started and it was a 2v3 situation I always ran. I noticed that a lot of ppl do that when I’m the first person who gets caught and die within seconds. So one day after getting flamed again for running away from a 2v3 situation I thought „maybe they are right“. So I started taking every 2v3 fight and only running so far that the enemies split up into smaller solo pushes. I won a lot more 2v3 than I thought I would and it helped me getting dia 2 last season.

So tldr: don’t run away if your are 2v3. Play smart and you win more than you think + you will get better in stressed situations.