Yeah, i bought the 5V isolator before i decided to go with an ESP32, but it still seemed to work fine with 3.3V so just went with it.
I'm not quite sure what you mean by "how is GND handled", afaik the common ground would be the GND wire to the PSU for both the BTS7960 and the ESP32/CNC Shield, i ...

Quick info:
So, i want to start this of with the fact that i am not experienced in pcb's and circuit boards, i am mainly a software developer, so i'll understand a small amount of electronics talk, but not a ton.
My issue is that my ESP32-S3 N16R8 seemed to have shorted, but i am uncertain as to ...