Overall, most of the daylight exteriors look VERY close to the original release, though! It looks SO GOOD! I can’t verify this, but I would almost bet money that Peter Doyle returned to do this new color grade. It definitely looks like his handiwork!
You should have made that bet! Initial review is up at TheDigitalBits (spoiler: he likes it), and indeed, Doyle did the re-grade. Lots of good technical info and sounds like the 4K HDR on BD is going to be nothing short of spectacular.
https://thedigitalbits.com/item/lord-of-the-rings-trilogy-2020-4k-uhd