Increase supply

There will always be milk in the breast. No amount of ‘cookies’ will increase your supply.
Breast feeding is all about supply and demand, the more you stimulate your nipples and release milk from your breast, you’re telling your body to make more.
You will also always have a slacker boob, mine is also my left, it never feels ‘full’. I do not pump well on that side either, but I know baby is getting milk from it, because when she unlatches milk falls from her mouth.
Make sure you’re well hydrated and well fed, as that’s the only thing that will help your supply as well as removing milk as often as possible.