u are not actually eating as much as u think.
advice? eat more. stick to wutever macronutrient ratio u are doing.

i believe the gaps in pec is genetic.
pectoralis muscle (major/minor) are divided into horizontal fibres. not vertically.
i think u cant really train a muscle bundle just at its certain ends.
there is upper and lower or mid but not inner/outer.
either u bulk your pec more by training, hoping the gains would properly cover that gap, or just deal with it.
i maybe wrong. pulled these out of my ass from common knowledge i got from my anatomy classes.

there is no pectoralis inneris.