RGB LED backlight is a terrible choice. Wide gamut but terrible color rendering.
Can I ask why it will produce terrible color rendering? In addition to commercial scanners that used narrowband trichromatic (RGB) light sources, hobbyists are creating their own RGB light sources to digitize color negative film claiming superior results and putting forward arguments why this is better: https://jackw01.github.io/scanlight/ (NB: Most film I shoot is slide film, which I’ve been told doesn’t benefit fro…
https://store.waveformlighting.com/collections/led-strips/pr...
Negative Supply use something similar in their light tables, though I don't know exactly what the source or spectrum is. They're highly regarded enough that I think it's not an issue.
You can also use LEDs for enlarging, but you need to be careful about buying the right bands for the paper. I've used Luxeon SunPlus with some success as you can buy the correct green/blue for the different contrast layers. Though for B&W, even a random 5500K module from Cree worked quite well.