Sorry for the slow reply piotrus3333!
I must admit I'm not very knowledgeable on the process of creating LUTs from resolve.
Would it be a case of using Resolve's CST's to go from linear to AgX and exporting that as a LUT?
I'd definitely like to explore this more - we've been using your AgX LUT pack for a while now and have been getting some great results.
Try the DCTL version of AgX first (link above). I consider it much better but this is all quite subjective. Note: DCTLs only work with Resolve Studio.
This particular DCTL only accepts Arri Wide Gamut 3 with LogC3 encoding as input - there is full drop down menu with other inputs but only this one combination works.
So your raw render from Corona would need CST from srgb linear to awg3 logC3 + AgX DCTL.
AgX DCTL will take you much farther than AgX Base (from my luts) to final look but you should still grade to taste (in LogC3, before DCTL).
Use
LUT Cube Analyzer node in Fusion for lut creation.
I'm attaching a crude example (works through CineonLog -
Logarythmic in Corona
LUT layer so clips the highlight at 13.52 float, should be ok for typical archviz scene)
(lut needs
string option, essential for Corona to turn off all the gamma shenanigans in frame buffer: float colormap.additionalGamma = -1.2)
edit: this lut takes raw render from Corona, transforms it through AgX Resolve
picture formation as the author calls it to display it on srgb display adding one of Arri's looks.
I hope this is somewhat helpful.