What I have found so far on the VEVOR BLDC 550W "servo" motor/controller set.

-What they call "SERVO" is not such, it is just a speed controlled brushless motor/ controller with HALL sensor feedback and 2 stop positions (when using the up/down needle attachment).
-It is not designed for handling midsize or large inertial loads, that is, it will not survive a lot of sudden stops, from high rpms, when used as a medium size lathe spindle, the reason: Lack of resistive brake load. All of the energy in the spinning chuck and rotating part will be delivered back to the dc link capacitors increasing the DC link voltage and stressing the output bridge and drivers.
-at least the one I disassembled, does not have pulse by pulse current limit, the overload circuit relies on the igbt bridge current developing more than 500 mV on the 0.015 ohm current sense resistor and thus triggering the bridge driver protection comparator (going over the 500mV reference voltage), then the overcurrent protection will trigger when the bridge current reaches > 33 Amps!!

The individual IGBTs are rated 600V 20Amps, as well as the antiparallel diodes, so the braking current will also stress them. The lack of a decent heatsink will not help either.
Due to all of the above, it is illogical to think about rotation reversal without stopping, it will destroy the output stage, that's why they used that convoluted way to reverse rotation.

Off course, all of the above is probably good enough for their intended application, mass production and a low cost product will make them cut many corners. But don't expect too much from them in other applications. The overall board design shares a lot with former ST evaluation boards. Even the set velocity input voltage range...