It's not technical, you are holding back way too much. This usually happens due to fear of exposing oneself. It could be tied into how expressive of your
emotions you are allowed to be at home.
It's way too emotionally safe a scared. Way too afraid of not getting it right, way too afraid of not sounding good.
This isn't a technical thing, this is an emotional barrier, to achieve the character and boldness required you will have to step out of your current
persona box. Stretch your current fearful persona.
It's not easy. You are too familiar with your current insecure, inferior self... you don't know how to be anything else for now. It has a lot to do
with age too...