5700KV in a 4x4 1/10 MT on 3S with stock gearing is asking a little too much, to be honest.

Cheapest option, which is the best option IMO, is to gear it down a little (or get smaller wheels/tires), to maybe a 12T Pinion and a 70T Spur, which is common.
It will still wheelie & backflip, but it will have a little less top speed. And the fan does help by at least 20 degrees if it is always on.