Resolve apparently still doesn’t support X-Trans, so that can be problematic for Fuji users.
One could probably create linear DNGs in camera-native colorspace and use those - e.g. demosaic it but don’t perform colorspace conversion.
“Linear DNG” is the terminology used for a demosaiced DNG, although in reality, whether demosaiced or not, DNGs don’t actually have to be linear… In fact in that S1H thread, it appeared like Atomos was shoving V-Log/V-Gamut data into DNGs. The data was most definitely not linear, it was log-encoded.
I can tell you that in general, unless it has a “shaper LUT” on the input, you really don’t ever want a 3D LUT to be operating on linear data because you want the LUT’s samples to be more perceptually linear as opposed to mathematically linear. But actual S-Log isn’t supported in dt, so you’re going to want to do something that chains your “look” LUT after some other colorspace transform. For example, one option might be sRGB gamma and Rec2020 gamut - you can create a HALD CLUT that converts from this to S-Log2+S-Gamut3.Cine, then use ffmpeg’s lut3d filter to apply your “look” LUT to that. Now you have sRGB gamma + Rec2020 gamut → your “look”. I’m assuming you can tell dt that the LUT output is rec709 gamma + rec709 gamut (most cinematic “look” LUTs are intended for 709/709 output).
(For some standards and colorspaces, you can safely make an assumption whether the identifier is talking about gamut or transfer function. This isn’t the case for sRGB or Rec709 - both of these specify both a transfer function AND a gamut, and it’s possible to use one without the other.)