The real answer is to record 10 bit videos instead of the 8 bit H264 we currently use, that gives 4x the dynamic range without having to do any clever tricks that damage the data, while only adding 25% to the bitrate, and probably less once compressed.
Maybe not too far away now, DJI recently released their Mavic 2 with 10 bit recording and they seem to be the leaders in our video technology, maybe the leading dashcam manufacturers will implement 10 bit in a couple of years time?