I've went through all of the steps here:
How to disassemble the propulsion wheels of the LEGO/DUPLO train engine base part# 28743 drivetrain?
which was a great learning exercise but unfortunately it seems like the actual motor itself has kicked the bucket. I can hear it activating when I try to push start it and kick it off from Bluetooth. It even works for a half a second.
Any idea where you can get a spare or even people who have been able to go in and fix it?