I looked up your original order and looks like you were batch 1. The reason that is important is because there was a motion control board design flaw on those early units that acted like a receiving antenna for noise on the USB communication lines. Before doing anything else I encourage you to perform the repair shown here: FIX: FireControl Freezing due to Interference (L1 Inductor Mod)
I’m confident that will fix the FireControl freezing problems (also make sure you are fully updated on FC and the firmware).
There was also an issue with Razorweld plasma cutters that caused intermittent misfiring (torch commanded to fire, only air comes out). There is a quick fix for that as well outlined in this Razorweld service bulletin: https://forum.langmuirsystems.com/uploads/short-url/nm14W58lgqhrXNzSADkKNONEsUD.pdf
I encourage you to perform both of these mods. Once thats done, get used to cutting with THC off for a bit. Once you see how things are supposed to work, transition to some THC on cutting.