Unfortunately water exists in the walls, adding weep holes wouldnt
change a THING but redirect the water away from your home.

Even water under the home can lead to high interior summer humidity
with possible mold growth.

plus whle you may drill into your floor and find gravel it may not be
gravel everywhere, the gravel may have been fill for a low spot
duiring home construction since gravel is way cheaper than thicker
concrete.

any chance of the system draining to daylight? thats the ideal choice