I have woeful aim and keep just spraying and going for RNG kills. Would playing some unrated with a sheriff only help? I don't play often enough to want to grind and do aimlabs for ages as I don't have the time for that, I'd rather just hop...

Many people have egos like this (even me) but the higher ranked player might have had a bad game or you just got lucky. Players that are higher ranked than you generally have better game sense than you to achieve their rank so don’t comp...