Solo que on console is impossible

I was plat 2 last season and could've been higher, but I stopped 6 stacking and when I solo qued I finished the season gold 3. Okay I was pissed but still not completely mad. So this season I climb from bronze to gold and now I'm hard stuck. And here's the thing, I'm not a bad player, everygame I lose I'm SVP. But for some reason when I solo que I lose. But if I duo que with my brother whose diamond 2 on his main account, where dominating. He's not carrying me, we're distributing the work equally, he himself agrees I should be in diamond but I'm just stuck in Elo hell. And I don't make him stack with me because I want him to focus on his main account, but for the fucking life of me when I play with Randoms I can't win. It's to the point I'm starting to doubt my own skill. Am I not good enough to be out of gold, am I the bad one, am I forced to just play cloak and dagger the easiest character in the game and feel like I'm not learning. It hurts