You can manually edit the gcode to see if printing white first works out better. Then search for a more repeatable solution if you often re-slice.

Manipulating gcode looks intimidating the first time but it’s really not that crazy. Cura adds comments to the gcode and you can look up the codes otherwise, I expect Pusa Slicer to do the same. You want to move the whole printing sequence of the white nozzle before the printing sequence of the second black one on the first layer. Keep the setup (heating etc) before that.