Hey Auntjemimma,
a “spindle” usually means a small, cylindrical induction motor. Induction motors forcibly need a VFD, because they are driven by three-phase electricity with a variable frequency (usually 0–400 Hz). A VFD is in principle an AC-to-DC-to-AC inverter which creates such current on the fly (see also differences between hand router and spindle ).
But there could still be what many consider as the best milling motor solution for hobbyists and semiprofessionals, which need no VFD nor any custom wiring, but are simply plugged into your domestic socket, but unfortunately Onefinity still does not offer a Onefinity motor mount for such milling motors (feature requested here as of 2023-Feb-28).