[SM-T377P] Low amperage when charging. Battery? Port?

Have a SM-T377P on a 2.1A charger with a meter which shows 5.2V and a steady 0.46A. The tablet shows the “charging” graphic on the screen. It’s been on the charger for about 20 minutes and has gotten to 1%.

How to tell if this is a battery problem or a charging port problem?

EDIT 1: It’s been about an hour and the battery is at 10%. Does anyone know how much amperage this device SHOULD be drawing?

EDIT 2: I’ve verified that it’s not the battery (swapped a new battery), cable (tried three different cables, all known-good), charger (tried three different chargers with different wattages, none below 10W, all known-good), or charging port (replaced the charging port).