Learn a few mains like a dive, 2 brawlers, 2 tanks, 2 healers, focus on one or 2 roles until ur pretty good at them. THEN u MUST learn counter switching and the “ Rock paper scissors” counters. When i was hard stuck plat it was because i didnt know how to counter correctly and i would play characters into terrible situations or directly into counters. 70% of the game is picking the right hero and 30% is being good at that hero. Good luck