There is no "right" answer.

The cslabs and machx stuff, I use, for a highly advanced lathe, is fantastic and vastly better than anything else I have seen.
But some other higher end industrial boards also have many commercial users and excellent specs.

It is quite hard and quite difficult and quite laborious to make a "good" industrial level cnc install.
Be it refit or new build.
My 3 axis lathe is 120 IO +/- and needs another 40.
On only 3 ac servo axis, so far.

Missing are servo faults, secondary optical homing, servo position tracking.
Probing.
Typical safety stuff interlocks, and IO for needed ancillaries in oil, tools, air, positions for toolchangers, in-pos, off-pos, etc.