The magenta zone is clipped in all three channels, which means that the reconstruction has literally nothing to reconstruct from (reconstruction is based on using the non-clipped channel(s) to correct the clipped one(s))
So using the filmic version is mostly a waste of time and effort. The easiest is to use the highlight reconstruction module in clip mode, that will at least ensure that such clipped zones stay white.
Oh, and adjusting the Raw white point isn’t really effective in such cases, it seems to be set correctly for a 12-bit raw file. The magenta cast is caused by the white balance, which amplifies the red and blue channels relative to the green channel. All channels are clipped in the raw file here, so that means that you end up with a magenta color (R:G:B is 1:1:1 in the raw, goes to ~2:1:2 after white balancing, and then stays that way, whatever you do)
I would use the highligh reconstruction module in clipping mode, and crop away the top part of the sky
Something like in the attached sidecar:
P1040843_01.RW2.xmp (7.2 KB)