Maybe just an idea here for Chris:
Brushless motors could be an option.
I don't know if you know odrives
There's a discord channel with a lot of great minds:
A v4 is currently in dev. It'll be single axis with a smaller form factor. Near motors drivers may be an option.
stepper motors is not a right direction for precision and speed for a arm robot ...
ODRIVEROBOTICS.COM 