Actually I can use it without problem because I invested in a professional equipment.
My question is meant to find a solution for the users (the atlas is meant to be used within Blender by the people who study the anatomy).
Eevee is ideal because it allows to navigate in real time with all the colors.
I tried splitting the data into several scenes:
‘Osteology’, ‘Arthrology’, etc. and it actually increased from 13Gb to about 20Gb the memory used.
I only linked-append the scene and unlinked the unecessary layers/main collections.
Did I miss something?