I have an MKS-SBASE V1.3 with integrated stepper motor drivers, but they don't have a physical way to change the current. I know there is a way to update the DRV8825 stepper current through Marlin, but I can't find it. Is it located in the advance configuration tab, or is a G-code I need to use?
They use DRV8825 stepper drivers which are much more prone to loosing steps than Allegro or Trinamic drivers
DRV8825 driver current cannot be changed from firmware like e.g. Marlin, Trinamic drivers can, but they are not installed on the board.
The MKS SBASE 1.3 has a potentiometer to set the current of each of the stepper drivers.
Don't see a physical potentiometer? That's correct! There are electronic potentiometers on the board. If you're using stock firmware: I can't tell you how to change it, but it must be possible. I'm using klipper and it has a section that by default sets the current to 1.0 A.