With DIP switches you can only use single microstepping mode all the time. For example, if you use 1/32, you will have decent resolution but your max GoTo speed will be very slow (for example 0.5 deg/sec), because Mega2560 can not send step signal faster than that. On the other hand, if you use 1/8 settings, your max GoTo speed will be 4x faster (for example 2 deg/sec), but resolution will suffer. That's why dinamic microstepping is prefered way with Mega2560.

So, for optimal performance you want Arduino to do changing microstep mode automatically for you. But, that means that you need to find a way change state of these dip switches by these arduino GPIO pins: 23, 25, 27 for RA and 31,33, 35 for DEC. This may hardvare (introducing optocouplers or something) and software hacking (adding custom driver pinmap)...

Or... You can go with something like ESP32 because it's fast enough to do everything in 1/32 mode.