In fact, I just worked out a simpler way to do it entirely in Resolve.
Because Resolve bakes the RRT and ODT into LUTs it generates in ACES mode (which is frequently an unwanted effect, but useful here) you simply need to temporarily add steps 1 and 2 above to the front of your node tree (using DCTL) when exporting your LUT. The image will not look right while you do this (although because as I pointed out above, ACEScct is “not a million miles from LogC” it won’t look entirely wrong) but the LUT will be correct.
Pardon the self promotion, but I sell a set of ACES DCTL files which can be used to do this.
(Note, I have proved this works in Resolve 12.5.5, but have not tested in v14 beta)