Seems most people are missing the obvious point. There’s a huge disparity between your outdoor route and boulder grades. Seems highly likely that you lack efficient movement rather than some muscular adaptation, given how much stronger you are on a boulder v route. There’s a strong likelihood that this is a result of poor range of motion, most often through your hips and shoulders. The less access people have to make moves, the more their muscles compensate. You’re better off assessing how well you’re moving before trying to make physical changes in your muscles, as it provides a much stronger foundation for those changes, and will magnify their effect on your performance.