Hi Thomas, It sounds like you have a lot going on here. Let’s start looking at some of these problems in order. Does the documentation that came with your laser engraver have any published speed, acceleration or Jerk settings? Have you made any adjustments to the settings in the controller? I see the Acctek akj1390h-2 as a controller but I have no information about your engraver. I am curious about speed settings and the health / capacity of the Stepper motor drivers, power supply and mechanical systems given the symptoms you describe.
This may be worth review: