It takes a lot more than just a mere 3D LUT, on movies.
For instance, there's what’s called a “show LUT”, which is used as a rough look on-set, but in post it’s a whole different story. LUTs have been over rated and misunderstood for a while. The blatant misinformation online contributed to it.
First and foremost, the LUT has to be compatible (format and color space specifications). Since they’re primarily created for digital cameras, most won’t fit for Octane.
They won’t be enough for a proper rendition either.
Here’s some reading about it.
Here’s a much superior solution to LUT. It doesn’t come with different looks but that’s possible, either via OCIO or in post such as in a compositing software (literally takes seconds to set it up).
It’s overwhelming, but worth it at the end and most importantly, an absolute necessity. Understanding the fundamentals of how an image is formed and pixels are managed allow for more technical and creative control.