Grbl on Arduino Uno (Elegoo) with DM542 + nema24 stepper motor not working
As you wrote, that you connected the positive pins of ENA, DIR and PUL to 5V, I guess you use the common anode connection scheme from the DM542's datasheet (the driver seems to have optocouplers for the inputs). That would mean the inputs are active low (a Pulse would be a transition from HIGH to LOW and then back to HIGH).

GRBL v1.1 has by default an active high pulse signal:


  By default, a step signal starts at normal-low and goes high upon a step pulse event. After a step pulse time set by $0, the pin resets to low, until the next step pulse event.


(from the GRBL github wiki). I guess, this is the problem. Please try to set GRBL for inverting the pulse signal with $2 (you may well find a corresponding setting inside bCNC.

Be sure, that GRBL is outputting the signals, that your driver is expecting in your connection scheme.