If there's space for one, there are many something-to-24v DC-DC converters on the market.

If you reckon four amps is enough then this:

https://www.amazon.com/Converter-Voltage-Reducer-Waterproof-Transformer/dp/B098D5R12Y/

If you reckon you need more then we've had good results with (the 12v version) of these at work:

https://www.amazon.com/Fafeicy-Converter-Module-Waterproof-Electrical/dp/B08V85SZTR

with them exposed to rain and heat.

With any of them, if you need direction-change, that's most easily done with a DPCO relay with the coil fed from a diode from the output of the direction switch (so in one direction the relay doesn't fire and is wired straight-through, and the other direction it fires and is wired to swap polarity of the converter's output). If you put a bridge rectifier on the input of the DC-DC converter, then it will always see the right polarity on its input terminals regardless of the direction the snow-blower is trying to turn the motor.