Autumn scene - Inversion of a negative scan by mirrorless camera

I created a FOSS Edits demonstration video using your file. Unfortunately, RawTherapee 5.9 doesn’t have a color profile for the camera you used to scan your film with. That Canon 1V was a great camera, btw.

I was pleased with my results, but I think I like your edit better. I love the composition you got here. Nice work.

I processed this with my own method that I documented here in by blog post: Scanning Color Negative Film.

I used my photographic paper curve which may help give the film look you are looking for. I find that if an image is underexposed that it is better to let the shadows go flat than to try to expand them.