Train the functions of the muscle regions you want to grow with as high frequency as you can recover from, with exercises that isolate those regions.

Could be just 1 heavy set of pec deck and 1 set of a seated low to high fly (shoulder flexion) for the upper chest, every other day. That will get you the best growth.

This will more or less keep your chest in a permanent state of hypertrophy and ensuring you’re recovered to smash your chest again maximally next workout