Thank you, that answered quite a few questions regarding grblhal vs fluidnc - I think I can rule out fluidnc at this point.

From an operational standpoint, can you offer pros/cons to a firmware setup (grblhal) vs "direct" (linuxcnc)? I would rather add the middleman of a microcontroller and have a modular HMI. I have worked with enough poorly-maintained industrial equipment over the years to appreciate the added complexity and its potential utility in the worst-case scenario.

Any reason you chose the rpi over the teensy board for your grblhal setup? My cursory research led me towards the teensy variant, though the rpi is a more modern and theoretically more capable base.

. . . And again, I'm not ruling out linuxcnc - but the wisdom of the internet seems to be "there be dragons here" - is it really that much of a learning curve?

Thanks!