At minimum?
Maybe the power to make someone have perfect executive function (have their intent and actions match within the upper limits of their physical, mental and emotional capacity including but not limited to solving their mental health issues and emotional hung ups, have a way easier time with learning disabilities or/and enhance learning processes, ability to unlearn anything useless, detrimental or unnecessary at the drop of the hat whenever and however they want to, access to all that potential and sound judgment within their current but increasing knowledge, intelligence, experience at the fullest extent, etc.) or severe executive dysfunction (make their experience, intelligence, abilities rendered basically useless, have them on a constant state of dysregulation that affects their mind and emotions, their mindsets and attitude, their memory and thought processes, their inhibitions and self control, prone to create more traumas, addictions, and develop worse mental illness, living filled with mistakes, missing details, bad decisions, overwhelm, etc. maybe curse them with bad luck on top of that).
Else;
A dial or a scale of anything in everything.
I can make something more or less of whatever function or attributes it's already there or is subject under.