Can you post a pic of your setup? Even though you say husbandry is pretty normal, there's no way to help unless others take a look at it.
But if you really want to get him to eat, honestly just buy a 6qt tub and follow this guide here... Follow it exactly, and your BP will eat. The concept of BP's is they need to feel hidden and being able to hide themselves completely in dark tight spaces in order to feel comfortable enough to eat. The bigger your setup, the more "clutter" and steps it takes to make a proper setup for a BP.
https://ball-pythons.net/forums/show...-hatchling-101