Mainsail/klipper is stalling/pausing during printing

Absolutely with @jakep_82 here:

  • Your steppers are supplied by 24V from the main PSU
  • All voltages on the MCU board are generated from the 24V main PSU
  • The power supply of the board and all board electronics are completely independent of the power supply of the RPi
  • The connection between MCU and RPi is digital, so not affected by unclean supply voltage unless it is so unclean that the high / low signal is destroyed, which then would result in a loss of connection
  • Undervoltage warnings of the RPi will lead to CPU throttling, which in turn will lead to the dreaded Timer too close or Timeout with MCU / Lost communication with MCU