uh my personal suggestion is
First of all, determine what the new CNC machine tool is used for? This is very important because everything that follows will be built around it
Such as engraving metal or acrylic or wood
Then determine the choice of ball screw or belt drive according to the needs, etc.
Spindle with servo spindle or ordinary spindle, air cooling, water cooling, etc.
Then there is the control aspect, whether to use a stepper motor or a servo motor